Eureka!

Eureka! is a moment that occurs whenever Horrid Henry gets an idea for what to do in different situations. It is followed by 'That's it!', making it into 'Eureka! That's it!'.
==Appearances ==
===Series 1===
*"Horrid Henry's Hike" - Because Henry wants to go home to watch Rapper Zapper, he has to go to the lake sooner.
*"Moody Margaret Moves In" - Henry has an idea to make his duty easier when Margaret's snooping in his stuff in his room.
*"Horrid Henry's School Fair" - Henry wants the Double Drencher in the school fair to spray all his enemies.
*"Horrid Henry Tricks and Treats" - Henry comes up with a plan to trick everyone during their Halloween as being dressed as a Dark Avenger to enjoy his.
*"Horrid Henry's Sports Day" - Henry decides to throw candies at every other racer for them to eat so he can win the 400 Meter race.
* "Horrid Henry and the Bogey Babysitter" - Henry knows Rabid Rebecca has Arachnophobia, so he puts them to scare her.
* "Horrid Henry and the Demon Dinner Lady" - Henry decides to refill lunchboxes to stuff Greasy Greta up and force her to go to the School Dinners room.
*"Horrid Henry Goes Swimming" - Henry tells Andrew about the latest news about the shark. By telling him, he swims out of the pool.
*"Horrid Henry Goes to Work" - Henry decides to photocopy Bill's bottom after he gets tired of photocopying these documents.
*"Horrid Henry Gets Rich Quick" - Henry wants to have more money by selling items and Peter as a slave.
*"Horrid Henry's Holiday" - Henry tries to bug off every camper by sabotaging their tents and activities.
*"Horrid Henry's Perfect Day" - Henry decides to be good because good children go to the fair like Perfect Peter.
*"Horrid Henry: Happy Birthday Peter!" - Henry can make Colin fail to escape after his countdown as it has elapsed by putting the key in the magical hat.
*"Horrid Henry's Time Capsule" - Henry has a plan to get Bunny back: dig for the time capsule and bring it to Peter.
*"Horrid Henry Runs Away" - Henry plans to run away from home.
*"Horrid Henry's Underpants" - Henry cannot handle with Great Aunt Greta's underpants, so he looks in the lost and found cupboard to look for a pair of underpants.
*"Horrid Henry Makes Some Money" - Henry can use the Fangmangler book to tell the Best Boys Club the story about a Fangmangler.
*"Horrid Henry's Dance Class" - Henry wants to do karate by borrowing Ralph's karate costume.
*"Horrid Henry Where's Fluffy?" - Henry tells Peter what to do and how to get Fluffy back from Margaret's treehouse.
*"Horrid Henry's Fairy Dance" - Henry has an idea to get Peter in trouble; fairies.
*"Horrid Henry Reads a Book" - Henry tries to win the reading contest by logging in more reports in his book report.
===Series 2=== 
*"Horrid Henry's Favourite Day" - Henry doesn't have to be good to Peter.
*"Horrid Henry and the Alien Invasion" - Henry knows that water can defeat the aliens.
*"Horrid Henry and the Lost Dog" - Henry wants to get Basher out of the house by going outside of it.
*"Horrid Henry and the Name Game" - Henry can use the phone and call Aunty Annie to name the black cat.
*"Horrid Henry Happy Birthday Steve!" - Because Henry said if only if it wasn't happening at the same time as the final, he would invite Rich Aunt Ruby and Stuck-Up Steve for tea.
*"Perfect Peter Pumps Up" - Henry takes Bunny to make fun of Peter. Meanwhile, at school, he gives Bill it to make sure that Peter is pumping up.
*“Horrid Henry’s Sercet Surprise” - When Henry thought the party was for himself, he decided to organise everything calling this Operation: Party Planner.
* "Horrid Henry and the Gross DVD" - When Henry wants to see Gross Class Zero, he goes into the clubhouse and has to vote on whether or not the club members want to watch it.
* "Horrid Henry and the Big Freeze Wheeze" - Henry puts Peter's Fairy Snowman on top of his Abominable Snowman to win a year supply of ice cream.
* "Horrid Henry and the Green Machine" - Henry can catch up with watching Gross Class Zero, play race tracks, and toast some bread for breakfast since the Windo-matic 5000 can produce their own electricity.
* Horrid Henry’s Smelly Stuff - Peter tells Henry that he’s an inventor and they invent things like perfume so he gets him to make some as Mum’s anniversary present.
*"Horrid Henry's Petsitting Service" - Henry decides to make a pet sitting service so that he can earn more money.
* "Horrid Henry on TV" - Henry can help himself if he can't get Margaret to help him.
* “Horrid Henry’s Fun Run” - During the Fun Run, Henry takes a shortcut through for woods.
*"Horrid Henry's Haircut" - Henry decides to take the perfect haircut as he was putting on a fake hairstyle so that he doesn't behave like a baby.
*"Horrid Henry Changes a Nappy" - Henry talks to Margaret and Susan that he can change a nappy.
*Horrid Henry Gets Spot - Henry sees the goldfish hiding up so high in the fish tank, he used the idea to escape the science room.
*Horrid Henry and the Gross Question - Peter tells Henry to find a cockroach to find the answer.
*Horrid Henry and the Zombie Hamster - Henry disguises Fang as a poodle to trick Peter who mentioned they can get one like Mum said.
*"Horrid Henry Takes a Shortcut" - Henry and Ralph can use the trolley from the supermarket to win the cross-country race.
*"Horrid Henry and the Antiques Rogue Show" - Henry knew that anyone can sign an autograph.
*"Horrid Henry and the Killer Boy Rats" - Henry knows that if Bert dunno, the Killer Boy Rats won't see him.
===Series 3===
*"Horrid Henry, Rockstar!" - Henry decides to write a letter to Ed Banger.
*"Horrid Henry and the Perfect Plane" - Henry can ask Mike to trade his comic for Mike's plane when he sees it in the store, and he couldn't get one since he had no pocket money.
*"Horrid Henry and the Booger Bogey" - Henry can try to steal Peter's Bogusem Beetlearius so he can prove that he's the king of the booger bogies.
*"Horrid Henry: Aliens Ate My Homework" - Henry puts cereal on Peter's head after he says, 'Aliens saved the day!'. Mum knew the cereal box was empty, so the aliens must have eaten them all.
*"Horrid Henry's Unhappy Day" - Henry goes to his room after he picks up the phone so he can call the Gross Class Publishers for another copy of this week's Gross Class Zero comic.
*"Horrid Henry, Rocking the World" - Henry wants to show confidence by copying Fang's movements.
*"Horrid Henry, Nothing But The Truth" - This time, Peter says it. He comes up with an idea to write a book about all the horrid things Henry's done.
*"Horrid Henry Delivers The Milk" - Henry has an idea to go the other direction around in a circle when Evil Eddy Edwards was ahead of them delivering the milk.
===Series 4===
*"Horrid Henry Knows It All" - Henry saw Brian beside him, and he knows it's Brainy Brian.
*“Horrid Henry Flicks the Bogey” - Henry says that Peter is a genius after he showed him the potion called ‘Odour Fartliness’.
*"Horrid Henry and the Single Sock Saga" - Henry decides to wash everything in the laundry machine so that they all smell the same.
*"Horrid Henry Gives It All Away" - Henry doesn't need his toys for a very long time, so he decides to give them all away and replace them with new ones.
* "Horrid Henry and the Purple Pass" - Henry called Bert a genius since Henry and his friends know that they're at the next stop.
*"Horrid Henry Helps Out" - Henry decides to write a letter to Big Bob.
*"Horrid Henry Gets the Gig" - Henry's gig is tomorrow afternoon, but he has detention with Mr Soggington tomorrow afternoon. So, he has a goldfish book that Mr Soggington loves to leave detention early.
*"Horrid Henry and the Number Gnomes Knowhow" - Henry wanted to borrow Peter's Number Gnome for the maths test.
===Series 5=== 
*"Horrid Henry's Uber Homework" - Henry knew that homework can be an app for it.
*"Horrid Henry: King Henry the Ninth" - Henry decides to block the bathroom's entrance by using a string.
* "Horrid Henry and the Awful Author" - To make Peter stop crying, Henry says to him it's not his fault.
* ”Horrid Henry: How to Be Good” - Henry gives Fluffy all the remaining house hotpot to eat.
* ”Horrid Henry and the Funny Bunny Hop” - Brian told Henry that people will pay money to the company.
===Other appearances===
* There is only one occasion where Peter says this catchphrase too. This only appearance is in "Horrid Henry, Nothing But The Truth", when Peter writes a story of all the things Henry has done after being so cross.
== Gallery ==
File:Early Eureka.png|Early (Seen in the early intro)
Screenshotter--HorridHenryHorridHenrysHorridRevengeMoodyMargaretMovesIn-15’02”.png|Series 1 and 2
Screenshotter--HorridHenryHorridHenryDeliverstheMilkHorridHenryGoesGross-8’37”.png|Series 3-4
Screenshotter--HorridHenryHorridHenryPlanetoftheGrapesHorridHenryEternalSchoolboy-4’40”.png|Series 4 and 5
Screenshotter--HorridHenryHorridHenryRockingtheWorldHorridHenryNothingbuttheTruth-14’19”.png|Peter's 'Eureka' moment
Category:Television Show-Related Content