Hystrodon is a rare Creature — Beast card from Onslaught (ONS), collector number 266. Current market price: $1.86 (foil $13.37), TCGplayer market prices via Scryfall.
Trample Whenever this creature deals combat damage to a player, you may draw a card. Morph {1}{G}{G} (You may cast this card face down as a 2/2 creature for {3}. Turn it face up any time for its morph cost.)