Tainted Harnesser

Whenever Tainted Harnesser enters the battlefield, choose target creature or land.
If it is a land, it becomes a swamp with "{t}: add {b}" and loses all other mana abilities and types. If
it is a creature, it has a base power and toughness
of 6/5 and is a black demon with menace, trample, and haste in addition to it's types.
"Seven of them stood in a chorus, channelling their
master's ambitions in to the uniling merging the
multiple fluidlings' and elementals' minds"