Thallid Devourer

At the beginning of your upkeep, put a spore counter on Thallid Devourer.
Remove three spore counters from Thallid Devourer: Create a 1/1 green Saproling creature token.
Sacrifice a Saproling: Thallid Devourer gets +1/+2 until end of turn.

Masters Edition II

At the beginning of your upkeep, put a spore counter on Thallid Devourer.
Remove three spore counters from Thallid Devourer: Put a 1/1 green Saproling creature token into play.
Sacrifice a Saproling: Thallid Devourer gets +1/+2 until end of turn.

Fallen Empires

During your upkeep, put a spore counter on Thallid Devourer.
o0: Remove three spore counters from Thallid Devourer to put a Saproling token into play. Treat this token as a 1/1 green creature.
o0: Sacrifice a Saproling to give Thallid Devourer +1/+2 until end of turn.