Yeah, I was a bit deflated initially thinking the octopus couldn’t attack again and most PCs per PHB can hold their breaths for a few minutes!

But being able to beat on the poor restrained PC makes it all good.

A side question: the PHB says there aren’t many CON ability checks, but holding your breath could call for one (hehe)...why do you think a spell concentration check is a CON saving throw rather than a CON ability check?