You can have any superpower you want but if any person ever finds out you have it you die immediately. Which one do you pick?

A magical deep-fried onion ring visits you at night and tells you you can have one single superpower. No matter which one. But you have to hide it forever. When someone finds out you have it you will die immediately. Which one do you pick and why? For example if you go for super strength and someone sees you lifting a car and points out it’s impossible you die. You pick invisibility and someone sees you turn invisible you die.