Crystalline Crawler is a rare Artifact Creature — Construct card from The List (PLST), collector number C16-54. Current market price: $0.68, TCGplayer market prices via Scryfall.
Converge — This creature enters with a +1/+1 counter on it for each color of mana spent to cast it. Remove a +1/+1 counter from this creature: Add one mana of any color. {T}: Put a +1/+1 counter on this creature.