Mossborn Hydra is a rare Creature — Elemental Hydra card from Foundations Promos (PFDN), collector number 107p. Current market price: $14.11 (foil $14.16), TCGplayer market prices via Scryfall.
Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.) This creature enters with a +1/+1 counter on it. Landfall — Whenever a land you control enters, double the number of +1/+1 counters on this creature.