Buttercup, the Mad King

Trample
Whenever Buttercup, the Mad King deals
damage to a player, gain control of target land
they control. It becomes a 4/4 Golem creature in addition to its other types.
"As we come closer to the Cradle, Atheris has seen fit
to reward me; a more potent form, to ensure I win him
his prize. I quite like it, though I must admit I miss
the flowers."