Jesper, Guardian Acolyte

Whenever another creature you control attacks or blocks, you may pay {1}{w}. If you do, put a +1/+1 counter on it, and prevent the next 3 damage
that would be dealt to it this turn.
Sacrifice Jesper, Guardian Acolyte: Creatures you control with converted mana cost 3 or less gain indestructible until end of turn.