I was trying to fusion summon Guardian Chimera using Sorcerer of the Swamp and Kaitoptera on field (and a monster in hand), where Sorcerer of the Swamp had been summoned by revealing Horned Saurus and banishing Kaitoptera.
Omega would not let me both monsters as fusion material, which confuses me. Sorcerer of the Swamp’s effect says: this card’s name can be treated as the banished monster’s, if used as Fusion Material this turn.
I was not given an option to choose if I would treat Sorcerer’s name as Kaitoptera or not, Omega just treated it as so automatically. The wording of the effect states that it is an optional replacement, so I am confused why I cannot summon Guardian Chimera with them both.