This idea, of giving your opponents permanents you control, has been explored several times in older sets
Full Party Whenever you attack with eight or more creatures, those creatures get +4/+4 until end of turn
Say that you have a Lost Leonin on the board which has a power of 2 and the infect ability
Cauldron Familiar Aside from being my favorite black card ever printed, Cauldron Familiar is an insane creature that has wrecked many formats, including Eternal ones such as Modern, thanks to its nasty tendency of being oppressive enough to shut down aggro decks, or even to go infinite with cards such as Samwise Gamgee and any sacrifice outlet
Ratadrabik of Urborg rewards legendary Zombies and adds vigilance, making it hard for opponents to penetrate your defenses
There are a lot of different shells for the card that I want to look at