Shroom Closet

Fungal Behemoth's power and toughness are each equal to the number of +1/+1 counters on creatures you control. Suspend X—. X can't be 0. (Rather than cast this card from your hand, you may pay and exile it with X time counters on it. At the beginning of your upkeep, remove a time counter. When the last is removed, you may cast it without paying its mana cost. It has haste.) Whenever a time counter is removed from this card while it's exiled, you may put a +1/+1 counter on target creature.

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.) Whenever this creature evolves, put a +1/+1 counter on each other creature you control with a +1/+1 counter on it.

At the beginning of your end step, you may exile target creature you control, then return that card to the battlefield under your control.