Fungus Sliver is a rare Creature — Fungus Sliver card from Premium Deck Series: Slivers (H09), collector number 21. Current market price: — (foil $0.83), TCGplayer market prices via Scryfall.
All Sliver creatures have "Whenever this creature is dealt damage, put a +1/+1 counter on it." (It must survive the damage to get the counter.)