Mercurial Pretender

(T: Add U.)

+1: Until end of turn, up to one target creature gets +1/+1 and gains first strike, vigilance, and lifelink. −2: Put a +1/+1 counter on each creature you control and a loyalty counter on each other planeswalker you control. −7: You get an emblem with "If a source would deal damage to you or a planeswalker you control, prevent all but 1 of that damage."

Whenever you gain life, put a +1/+1 counter on this creature.

Flying, vigilance 1W: Prevent all damage that would be dealt to another target creature this turn by sources of the color of your choice. 5WW: Prevent all damage that would be dealt to target player or planeswalker this turn by sources of the color of your choice.

Enchant creature Enchanted creature has double strike. (It deals both first-strike and regular combat damage.)

When this creature enters, you may search your graveyard, hand, and/or library for an Aura card and put it onto the battlefield attached to this creature. If you search your library this way, shuffle.

Target player gains 2 life for each creature on the battlefield.

Sliver creatures you control have "When this creature enters, you may exile target creature an opponent controls until this creature leaves the battlefield."