Yurothmeit, God of the Swamp

As long as you control six or more Swamps, Yurothmeit, God of the Swamp is a creature and has indestructible.
Whenever a creature blocks Yurothmeit, that creature gets -2/-2 until the end of turn.
At the beginning of each end step, if Yurothemit was blocked by three or more creatures this turn, sacrifice it.