In my current OOTA Group my party fought against a rocktopus. They attacked them from the ceiling out of reach for melee attacks.
Is it possible for the players to ready an attack with the trigger "when one of the tentacles attack I'm gonna hit it"?
Normally I would say no. If your target attacks you with a weapon with more reach and is out of your reach it shouldn't be possible to hit them with your readied action. But the melee weapon (the tentacle) is part of the rocktopus and I am not sure how to handle this situation.