Hybrid Monsters (雑種モンスター Zasshu Monsutā) are a type of Monster Card that exists in the Extra Deck. The original concept of Hybrid Monsters was created by Ultimate Dragon Knight, but the type has been refined into a more unique type of monster by Taylor Gorrell. The color of their card frame is a bright green, a different shade than the one used by Spell Cards.
Originally, Hybrid Monsters were almost identical in use to Fusion Monsters, with the exception that Hybrid Monsters always had at least 1 Spell or Trap Card as a Material.
The current version of Hybrid Monsters are quite different, taking elements from different Summons. This version of Hybrid Monsters can only be Hybrid Summoned through Spell and Trap Cards, but similar to Ritual Spell Cards, these cards are their own Type: Splice Spell Cards and Splice Trap Cards (collectively known simply as Splice Cards). Rather than list any Materials that are needed, Hybrid Monsters only list the proper Splice Card that is needed to Hybrid Summon them, as the usable monster(s) are listed on the Splice Card's Splice Effect.
While most Hybrid Monsters have Levels, those that specifically state an Xyz Monster or a Composition Monster in their Splice Cards often have Ranks or Qualities, making Hybrid Monsters the only monster type able to have more than one power indicator.