A Ritual Monster is a type of card in the trading card game Yu-Gi-Oh!. These monsters are special because they can only be summoned by performing a specific ritual, which usually involves a Ritual Spell Card and the sacrifice of other monsters. This summoning process allows players to bring powerful creatures into play, often with unique abilities. To summon a Ritual Monster, players must have the corresponding Ritual Spell Card in their hand, along with the required monsters. Once the ritual is completed, the Ritual Monster can be used in battles against opponents, providing strategic advantages in gameplay.