- "Cannot be used as Fusion Material otherwise" is not treated as an effect. (It is a requirement for using "Fusion Parasite" as a Fusion Material.)
- The monster effect "This card can be used as a substitute for any 1 Fusion Material whose name is specifically listed on the Fusion Monster Card, but the other Fusion Material(s) must be correct" is not an Ignition, Trigger, Quick, or Continuous Effect. (It does not target.)
- The monster effect "If this card is Special Summoned (except during the Damage Step): You can Fusion Summon 1 Fusion Monster from your Extra Deck, using monsters you control as Fusion Materials, including this card" is a Trigger Effect. (It does not target. It cannot be activated during the Damage Step.)
- When Fusion Summoning with the monster effect of a successfully Special Summoned "Fusion Parasite", its own first monster effect is applied, and the other normal Fusion Material Monsters are sent from the player's field to the Graveyard. (Face-down Defense Position monsters in the player's Monster Zone can also be sent to the Graveyard as Fusion Material Monsters.)
- Applying "You can Fusion Summon 1 Fusion Monster from your Extra Deck" and "using monsters you control as Fusion Materials, including this card" are not treated as being done at the same time.