Challenges

== Get Back! ==
Starts you with 20/20, max knockback, Soy Milk, Mutant Spider, and Dark Matter (for the fear effect). Also the Inner eye if it stacks with Mutant Spider.
== My God! ==
by Anonymous
You start with all Angel Room items. No Item, Angel or Devil rooms spawn. Ends after beating isaac.
== Through the Fire and Flame ==
by Anonymous
You start with the Candle. Fire doesn't do any damage, but hellfire still shoots. All monsters do 1 heart if damage. Treasure rooms/shops still spawn, but all spacebar items will revert back to the Candle after that floor. Ends after beating Satan.
== I am the MAGICIAN! ==
by elias137
In this challenge Isaac starts with Spoon Bender and Little Steven and The Inner Eye. No treasure rooms and no slot machines. The challenge is succeeded when you beat Mom! You will unlock homing laser tears (Technology3)
== I and my friend is bum ==
by elias137
In this challenge Isaac starts with Box, Bum Friend, and The Peeper. No Treasure Room or beggars (normal or devil). you must beat Mom to succeed the challenge! You will unlock Rich Friend!
== The Dentist ==
by Anonymous
In this challenge Isaac starts with Monstro's Tooth, Tough Love and PHD. Treasure rooms will not be generated and you must kill Mom's Heart to succeed. After completion, the trinket 'Second Chance' is unlocked.
== Laser Eyes ==
by Anonymous
In this challenge, you start with Technology 1 and 2. There are no treasure rooms. You must make it to Mom's Heart to succeed. After winning, you unlock the Flashlight trinket.
== Me and My Friends ==
by Anonymous
In this challenge, all randomized items will be replaced with random familiars, only bosses can drop Stat Ups. Isaac starts with the Monster Manual. The Headless Horseman/Conquest will always drop Cubes of Meat. Only one Treasure room per chapter will spawn, 1 each in the Basement, Caves, Depths, Womb and Sheol (alts as well). For a total of 5 free treasures across the entire challenge not including random drops from chests, beggars and such. A treasure from an arcade/machine will instead grant 5 free attack flies. Goal is to complete chapter 5 (either path).
Wouldn't work. You can only have up to 4 familiars at once. -Yumil Recian
== Destruction Derby ==
by LucasK
In this challenge, you start with Bomb Bag and Kamikaze. Item rooms and shops would have only "destruction" item pickups (shops still would have other things such as hearts and only "The Tower" as a card), like Mr. Mega, Mr. Boom, Bobby Bomb, Boom!, Notch's Pickaxe, well...all of these items that can cause explosive damage or destroy rocks, or affect bombs. Only Bosses would drop other types of items. The Challenge would end after beating Mom. Completing this Challenge would unlock the Dynamite Pack and the Trinket "Golden Bomb" (See Trinket Ideas). The Dynamite Pack item would let you Shoot Dynamites that would explode after touching anything. This item would recharge at every 3 rooms.
== Shopping Spree ==
by 00_13
In this challenge, you start with A Dollar and Bill, and 5 keys. Treasure rooms are replaced by shops. The challenge is over when you reach Mom's Heart.
Suggestion by Anonymous: Perhaps make all shops spawn at least 1 active item or passive upgrade in addition to this.
== The Masochist ==
by Keygenocide
In this challenge, you start with IPECAC and My Reflection. Boss drops are normal. 1 treasure room per chapter (ie: Only 1 across both Basements, 1 across the Caves, & Depths). Treasure rooms cannot contain items that change your weapon (Technology, Dr. Fetus, Mom's Knife, etc). The challenge is completed after beating Mom's Heart/It Lives. Completion of the challenge would unlock The Vest, a rare item found in treasure rooms that halves all explosive attacks, but also has a 20% chance to negate all damage taken from an explosion.
IPECAC and My Reflection? I hate you. But I love you at the same time. -Yumil Recian
Added in Rebirth as Suicide King
== Scared Of Heights? ==
by Anonymous
No flying items. Conquest and Headless Horseman do not spawn. The challenge ends after defeating Mom's Heart/It Lives.
Suggestion by Pittoo: Maybe you COULD run into Headless Horseman or Conquest, but they drop Cubes of Meat instead of flying items.
== I want my mommy! ==
by tracotaper
You begin with all Mom items. No treasure rooms, trinkets, or shops. Bosses drop health rarely, and you can only do alternate floors. Goal is Isaac. Item unlocked from winning is Mom's Ring, a trinket which randomly make enemies run away and increases your chance of getting hearts.
I don't know, I mean if it includes starting with moms knife then....- QW3RTYPOUNC3S
== Sugar Maniac ==
by Pittoo
Start out with max speed, Speed Ball and Cat O' Nine Tails.Rooms with spikes are more common to appear.Challenge ends when you kill Mom's Heart. Reward is Super Speed(trinket) which will randomly increase tear speed.If you already have Super Ball or Cat O' Nine Tails,it will stack with it and make the random shots even faster.
== Heartless Isaac ==
by Anonymous
You start regularly, but you can't collect anything heart related, (no hearts, spirit hearts, eternal hearts, ect.)
So... can you still get HP Up items? Or do you have to pull a near perfect run? I'm confused. -Yumil Recian
== The binding of Meat boy ==
by Anonymous
You start out with only SMB super fan. There are no shops or item rooms. You must defeat a harbinger to win.
SUGGESTION if you don't find any Harbingers, Mom's Heart is replaced by one.
Comment by ZangiefB: What if you find Famine in Basement 1?
Famine. Game over. I don't much care for this challenge, to be honest. Just replay the first few levels 'till you win. -Yumil Recian
== Proper Christian ==
by DarkDXZ
You start out with one eternal heart, the Scapular and the Bible, as well as Maggy's Faith. There are no treasure rooms. The challenge ends once you defeat the Mom's Heart/It Lives!
Reward - COMING SOON.
== Have a Heart ==
by Anonymous
You start with no full hearts, but instead 10 soul hearts. No health-related items appear whatsoever either. The challenge is over when you reach mom's heart.
Reward - Unlocks the Love Heart, an item that increase your maximum health by one. Takes 10 rooms to recharge.
Suggestion to have a Heart 'By Lazerguy555:
First, I think you meant beat Mom's Heart.
Second, Love Heart is waaaaaaaaaaaaaaaay to OP. Maybe make it so it gives you an eternal heart instead, or possibly like 5 spirit hearts? (Also, since it takes 10 turns to recover, wouldn't it be insane if you had curse of the lost on The Womb/ Utero?)
To be honest, I don't have much of a problem with Love Heart. After all, Prayer Card is a thing, remember? It gives you 1 Eternal Heart (effectively increases your max health by 1) and has a 6 room recharge. Also, I like this idea. -Yumil Recian
== Pony super star! ==
by Anonymous
You start with a white pony,10 pony heads and star of david.You must kill ??? to end the challenge.
Reward-COMING SOON TOO!
== Tons of cool stuff ==
by Anonymous
In the challenge you can only get WotL items, bosses, enemies and floors.
Play as Isaac without the D6. Sacrifice, Library, and Angel Rooms are twice as common.
REWARD: lamb eye {trinket} which makes wrath of the lamb stuff appear more.
Tons of Cool Stuff is a stupid name. Maybe name it 'Advent of the Lamb'? It would give people a good look at the new WotL items.
== Archangel Isaac ==
by Anonymous
You start with all Archangel items and the Skyward Horseman trinket (Fan idea trinket). There are no Treasure rooms, Devil rooms, Curse rooms and Spike rooms. You have to defeat Satan.
Reward: Angel Phone trinket
== Pee Man ==
by ZangiefB
You start the game with Number One and Lemon Mishap. No treasure rooms generate. To win, you have to defeat Mom's Heart.
Reward: Coming soon to a basement near you.
SUGGESTION:you should also start with the peeper
== We Are the Champions ==
by 00_13
All enemies are champion variants. ALL ENEMIES. Super Sins spawn where normal Sins normally spawn. No pickups are dropped by the Champions.
Have fun! You win when you defeat Satan.
Reward: The Enchanted Die
Comment by ZangiefB: This is insane.
Sounds impossible as fuck. I love it. (I needed a challenge anyway!) -Yumil Recian
== I'm MOM!!! ==
by Mirceamix123
Play as Magdalene. You start with all items of mom's (yes and knife). No treasure room .
Reward:You Unlocked a unholy item "Satanic Heart"
Aaaand what does this item do exactly? -Yumil Recian
== Strike of the bosses ==
by Fabianator
You are Isaac with no Items. There is a 50% chance to get a treasureroom. each floor is 2-4 rooms: A start room, a boss room, a monster room and sometimes a treasure room. In this challenge, you must defeat every boss in a random order.
Reward: You will unlock the Item "Book of Bosses". This will make you a random boss spawn for the current room, which will not hurt you but the enemies.
== Bloody dangerous ==
by (the guy who made the "bad digestion" item)
You start as Samson with Blood Rights, Blood Bag, and Bloody Lust. All shops are replaced by sacrifice rooms or cursed rooms. get to satan to win.
Reward: The "Meatwheat", which severely increases attack, and increases health by 1.
Could you... define 'severely increases'? -Yumil Recian
== Infested ==
by (the guy who made the "bad digestion" item)
You start as Isaac with The Infestation, The Parasite, and The Tick. no shops, no item rooms. beat Mom's heart to win.
Reward: The Leech, Shoots a fast Leech enemy-like bullet that when it hits an enemy, leeches HP.
== Emperor of Flies ==
by Anonymous
You start as Isaac with Halo of Flies, Pretty Fly, The Mulligan, Infestation, Distant Admiration, Forever Alone, Skatole, and the Fish Head trinket. You cannot replace your trinket, and there are no items, except spacebar items and boss drops.
== Cry Some More! ==
by Anonymous
You start as Isaac with Odd Mushroom (Thin) and Cancer trinket. It cannot be replaced, but collecting Mom's Purse will allow to hold the extra trinket. 
Only one treasure room appears per chapter (Basement/Cellar; Caves/Catacombs; Depths/Necropolis). The challenge ends upon defeating the boss in Chapter 4 (Womb 2/Utero 2).
== The Enlargening ==
by pillbox15
You start as Isaac, and every 3 rooms, you get a modified version of the magic mushroom but doesnt improve your stats, just makes you bigger! So you have to rush to beat the game or be too big and have severely messed up hitboxes.
Reward: Ultra-Shroom, this ups all stats by 2 excluding 1 random stat that will be upped by 3, and it makes you look a lot bigger. This item is generally as rare to find as Dr. Fetus.
== Soooo Hardcore ==
by KirbyCz
You start as ??? with Polyphemus, Brimstone, Squeezy, all mushrooms (Magic Mushroom, Mini Mush, both Odd Mushrooms) ,Wooden Spoon, The Belt, Raw Liver, Wafer, Candle, Polaroid, Halo, Halo of Flies and Guardian Angel. No items, except for ones dropped by bosses. You cannot obtain any Spirit Hearts by any method (health up, book of revelation, the nail). Ended by defeating the Destroyer.
Reward: The Destroyer Soul, this increases all stats by 3, makes you fly, increases your tears' damage and size, adds a homing effect to them, and increases Isaac's size (more than Magic Mushroom). Rarer than Epic Fetus. Only found in Secret Rooms (Rare as F**k) and Top Secret Rooms (Also rare but not that much.)
I fixed up your grammar. Also, destroyer is broken as fuck. Battery + D6 + X-Ray Vision Glasses and I can get it easily with Isaac and proceed to destroy the game. -Yumil Recian
You forgot the 1-up.
==Spike was the floor==
by WitherSnow
You start out with your speed doubled. You also have The Belt and any other speed increasing items. However, every other stat is set to 1 (including luck and health).
Spikes spawn more often than before (75% more common), even in the Basement and Cellar. Any floor can have spikes in it. By beating the challenge you unlock the Trap Spike. It is a spacebar item with a 2 room recharge.
Fixed up your grammar. I'm assuming the Trap Spike places a spike on your location? Or is it like the candle, notched pickaxe, etc. and you activate it and then select a direction to place the spike (so that you don't take contact damage from it?)
Here's my idea for the challenge instead, that makes it a lot simpler. All wall blocks are instead replaced with spikes. Start with The Belt and Growth Hormones.' How's that sound? -Yumil Recian
==The Cat Came Back==
by Yumil Recian aka that guy that fixes grammar
Play as Isaac. Start off with Guppy's Tail, Dead Cat, and Guppy's Head (replacing The Dice). No Treasure Rooms. Goal is Mom's Heart/It Lives. Finishing it unlocks Guppy's Claw, which is a passive item that adds +1 damage and +2 Soul Hearts on pick up (similar to an attack-increasing equivalent to Squeezy).
== The Son of Sin ==
by Anonymous (seems legit)
Play as Isaac. Start off with book of Sin, Dead bird and Whore of Babylon, and you can't replace the book of sin with any other item. All normal rooms are mini-boss rooms, but special rooms aren't (shop, item room, boss room, sacrifice and curse rooms, secret rooms...) Ends when you defeat Mom's Heart.
== Trial of Solaris (WIP) ==
by Grahkon (AKA some newb you've never heard of)
Note: this challenge is not like any others you've seen so far. remember that.
This challenge takes place over 11 floors, the 11th is the boss.
you start as Isaac with nothing, but will be given item through the challenges
==== Floor 1: Pluto ====
(WIP)
==== Floor 2: Neptune ====
(WIP)
==== Floor 3: Uranus ====
(WIP)
==== Floor 4: Saturn ====
(WIP)
==== Floor 5: Jupiter ====
(WIP)
==== Floor 6: Mars ====
(WIP)
==== Floor 7: Luna ====
(WIP)
==== Floor 8: Earth ====
(WIP)
==== Floor 9: Venus ====
(WIP)
==== Floor 10: Mercury ====
(WIP)
==== Boss floor: Sol ====
(WIP)