Thrawn, Swamp Denizen

Thrawn, Swamp Denizen costs {1} less to cast for each swamp on the battlefield.
Thrawn, Swamp Denizen gets +1/+1 for
each swamp on the battlefield.
Whenever a forest enters the battlefield
under your control, you may have Thrawn, Swamp Denizen fight another target creature.
Whenever a creature dealt damage by Thrawn, Swamp Denizen this turn dies, create a number of X/1 green and black saprolings equal to that creature's toughness, where X is the number of forests you control.