Thallid Shell-Dweller is a common Creature — Fungus card from Time Spiral (TSP), collector number 226. Current market price: $0.14 (foil $0.70), TCGplayer market prices via Scryfall.
Defender At the beginning of your upkeep, put a spore counter on this creature. Remove three spore counters from this creature: Create a 1/1 green Saproling creature token.