Forest Hydra

Forest Hydra enters the battlefield with X +1/+1 counters on it
Whenever Forest Hydra deals combat damage to a creature, that creature gets a poison counter for each +1/+1 counter on this creature and gets 'at the beginning of your upkeep, tap target land you control for each poison counter on this creature'
'The deadliest creature we came up against was the Hydra, it had many heads, and all of them were dangerous' - Thasson