"Converting" spells, traps and troops

I have seen many people come up with ideas that follow the same basic pattern:

The spell/troop/trap turns enemy clan castle troops or attacking troops and/or defences against the attacker/defender depending on what it is.

This is ridiculous and overpowered. There are thousands of variations upon this and all of them share the same basic qualities: they are OP, The prices are ridiculously cheap for what they are and the storage space is ridiculously low.

Please, before making a thread here remember to check whether it is original or not, and use common sense to figure out whether it's OP or not.

Thank you for your time, and clash on