A Crossover Monster is a type of monster that exists in the Extra Deck. The original concept of the Crossover Monsters was created by sgibson, by the card is newer to other cards from the Extra deck. The frame for this card is Crimson. The Crossover monsters attributes are different they contain up to 2 or more attributes (example DARK/LIGHT exec)
To summon a Crossover monster you must use 2 or more monsters you control either on the field or in your hand with different attributes and tribute them to Crossover Summon 1 Crossover monster from your Extra deck to the field and their attributes are half and half.
The Crossover monsters contain 2 or more attributes. Their card effects are both different and the same to other monster effects. Crossover Monsters can only be Crossover summoned to one of your Extra Monster Zones from your Extra Deck.