Weir, Mutations Crafter

When Weir, Mutations Crafter enters the battlefield, put a mutation counter on another
target creature you control.
As long as a creature you control has a mutation counter on it, it has base power and toughness
4/4, trample, and "This creature is a Mutant in
addition to it's other types."
{t}: Put a mutation counter on another target
creature you control.