(Fetid Rainforest isn't a spell.)

At the beginning of your upkeep, Fetid Rainforest deals 1 damage to target creature you control.

Fetid Rainforest is indestructible. (Destroy effects and lethal damage don't destroy it.)

, Pay 1 life, Sacrifice Fetid Rainforest: Search your library for a Swamp or Forest card and put it onto the battlefield, then shuffle your library.