[ Well, it's not like he gave a gag order, and if he'd wanted to, he's had time to do so. ]

It's a type of science that allows cloning and the like through appearification. An appearifier takes an item from a specific point in time; if it's going to cause a paradox by taking it, you get slime instead. To create a person - say, me! - you need slime from more than one source. To create a clone, you just need slime from one source.