Enlist

Enlist is a keyword ability on creatures that allows the player to buff creatures. It can be considered a modern take on Banding and was introduced in Dominaria United.
==Description==
Enlist represents an optional cost to attack. As you attack with a creature with enlist, you can tap a different untapped creature you control that isn't attacking. That creature — the enlisted creature — can't have "summoning sickness," meaning it's been under your control since your turn began or it has haste. 
When you enlist a creature, the attacking creature that has the enlist ability gets +X/+0 until end of turn, where X is the power of the enlisted creature. This bonus is calculated as this triggered ability resolves. If the enlisted creature isn't on the battlefield at that time, use its power from when it was last on the battlefield. 
The reminder text of Enlist notably references the informal term summoning sickness.
===Comparison to Banding===
Enlist is not a complicated mechanic besides the odd "non-summoning sick" clause. In order to make the comparison to the notoriously complicated Banding, one considers the basics of a two-creature Band in combat:
*Two attackers form a band. They can be blocked by a single creature, but in exchange controller of the band gets the choice to assign combat damage.
*For a favorable defender's combat, the blocker needs to have sufficient power to match each attacker's toughness in the band, as otherwise, the attacker assigns blocker damage to the tougher creature, and neither will die.
*The blocker will take the combined damage.
For Enlist:
*An untapped creature without summoning sickness is tapped. This is functionally similar to attacking, but without entering combat.
*The combined damage is reflected through the +X/+0 effect.
*The assignment of combat damage is a forced tactical choice from sizing. 
The defender is forced to engage only with the Enlister, most of which are poor attackers without Enlist. Many had higher toughness, which hence results in something to the effect of forcing the defender to assemble enough power to match, while the lower-toughness Enlisted creature survives.
==Rules==
==Rulings==
*Creatures with defender or ones enchanted with Auras like <c>Pacifism</c> may be enlisted. 
*You can't enlist a creature that's attacking, even if it's untapped because of vigilance.
*Once the ability resolves, the +X/+0 is locked in. Changing the power of the enlisted creature or removing it from the battlefield won't affect the creature with enlist.
*The attacking player chooses whether to tap a creature for an enlist ability immediately after they tap the creatures that they have chosen to attack with. You can’t choose to enlist a creature later.
*To enlist a creature, that creature must be untapped, it must not be attacking (even if it has vigilance), and it must have haste or have been under that attacking player’s control since the beginning of their current turn.
*When a player taps a creature for an attacking creature’s enlist ability, that attacking creature gets +X/+0 until end of turn, where X is the tapped creature’s power. This is a triggered ability that goes on the stack immediately after attackers have been declared in the declare attackers step.
*You may tap only one creature for an enlist ability of an attacking creature, and a single creature can’t be tapped for more than one enlist ability.
==Examples==
==References==