Use Clan Castle spell for live raid defense
Sorry if this has been suggested but: now that we get 1 slot in the clan castle for a donated spell, I'd love to be able to use it for defense if I happened to catch someone raiding me live. Granted this would only really work for poison, but it would be fun to shock an attacker with a poison spell from time to time.
I don't recommend for war, but for defense against random raids that you happen to catch as they are happening, I think it would be a fun addition.