While it's cool and all, it's not that magical. It takes a lot of energy and time for a starfish to regrow an arm. Plus, it leaves them vulnerable to predators while they're regrowing parts. So yeah, it's a neat trick, but it's not all sunshine and rainbows.
Tom and Jerry would prob just end the world in a nuclear cat-mouse apocalypse. We all know it's what they've been building up to for decades, right?