Had a possible idea for when Rainbow Rocket is used. If Giovanni is used, after beating him Mewtwo could have some revenge on him since he did order her to be made into a weapon with pain but she wont kill him since she has now embraced love and is ready to let go of the pain inflicted on her by his organization. Since she has been training with Lugia for a long time in anal she would always have a giant dildo in her ass to be ready when the MC wants her. So she would take the giant dildo out of her ass and shove it all the way up Giovanni's ass completely and leaving it in and just stays long enough make sure he is not dead before leaving to be with the MC. Giovanni has been going to multiple dimensions and wreaking havoc so instead of leaving almost scot free this can happen to break his spirit and allow Mewtwo closure on her past.