Old Entity Cthugua

【Regarding the ① effect】

This is a Trigger Effect that can be activated in the Monster Zone.

This is an optional effect that can be activated when this card is successfully Synchro Summoned.

Only Rank 4 Xyz Monsters that are face-up in either player's Monster Zone can be returned to their owner's Extra Deck by this effect. (Xyz Monsters in face-down Defense Position, etc., are not returned to their owner's Extra Deck.)

【Regarding the ② effect】

This is a Trigger Effect.

This effect must be activated when a Fusion Monster is successfully Fusion Summoned using this card as material.

If this card is used as Fusion Material and sent to the Graveyard, this effect activates in the Graveyard; if it is banished face-up, it activates while banished. (It activates in the location where it was first sent. Also, it does not activate if it is returned to the Extra Deck as Fusion Material.)

【Regarding the ③ effect】

This effect is not classified as an Ignition Effect, Trigger Effect, Quick Effect, or Continuous Effect.

A monster that is Xyz Summoned using this card as an Xyz Material will gain the effect marked with "●". (This is not an effect activated by this card itself.)

【Regarding the effect of "●"】

This is a Trigger Effect that activates in the Monster Zone when a monster that used this card as an Xyz Material is successfully Xyz Summoned. (This effect is mandatory.)