The ability to steal someone else ability on this earth from every human that poses superpower.
then ill go with the ability to steal back the ability someone stole from you because you had superpowers... which frankly isnt that un-usefull anyhow
Only thing is, i dont know any person with superpower :) P.S. Imagine you can steal superpower in point 4
Few more useless abilities:
1. Freezing all water you touch or making air poisonous on fisical contact.
2. Ability of get weak all of a sudden.
3. Ability to spoil everything you want to use.
4. Ability of forgetting something in random moments... wait this one exist, it is called alzheimer