"Hex-Sealed Fusion", known as "Fusion Seal Organism" (ゆうごうじゅいんせいぶつ, Yūgō Juin Seibutsu) in the Japanese version, is a series of Rock monsters that have the same two effects which support Fusion Monsters.

The two effects are as follows:


  • When resolving the second effect, the "Hex-Sealed Fusion" monster can be treated as a Fusion Substitute Monster with its first effect.