Target 1 "Purrely" Xyz Monster you control; Special Summon 1 Level 1 "Purrely" monster from your Deck, but negate its effects, then Special Summon from your Extra Deck, 1 "Purrely" Xyz Monster with the same Rank but a different Attribute than the targeted monster, by using that Special Summoned monster as material. (This is treated as an Xyz Summon.)
Then, you can attach 1 card from your Deck to that Xyz Summoned monster, with the same name as a "Purrely" Quick-Play Spell attached to the targeted monster.