(Dragonskull Wildwood isn't a spell.)

At the beginning of your end step, if you didn't cast any spells this turn, Dragonskull Wildwood deals 1 damage to you.

Dragonskull Wildwood is indestructible. (Destroy effects and lethal damage don't destroy it.)

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