Convulsing Licid is a uncommon Creature — Licid card from Stronghold (STH), collector number 77. Current market price: $0.18, TCGplayer market prices via Scryfall.
{R}, {T}: This creature loses this ability and becomes an Aura enchantment with enchant creature. Attach it to target creature. You may pay {R} to end this effect. Enchanted creature can't block.