[@Bai Suzhen] That degree of reverse-aging sounds like a pretty strong power for this stage in the game. Buuut I love her, so I'm gonna approve it all before I can talk myself out of it! XD Copy her to Characters and start playing when you're ready.

Just keep in mind that powers are about 2 or 3/10 right now. Muriel can stretch into a long, thin, and/or flat version of herself. If you want to do fancy Elastigirl stuff like turn yourself into a speedboat, you gotta earn it.