This is first impression of the new feature and I am not sure if I have all my facts correct however from what I can tell is that a nearby dumbo octopus creates a bubble around the player when their air drops below half way. This is a pretty cool feature however as of current it seems to last indefinitely (or really long) until the player surfaces and the player can just use the octopus straight away again. This basically removes all need for water breathing potions just bring a bucket of dumbo octopus. The octopus also only sometimes seems to pathfind to the player to give the effects other times you just have to swim into it. There is also no indication that the player has been bubbled expect for the bubble viewable in inventory and third person.

I am not sure if this is all intended however I would reccomend these following changes in working towards balancing the mechanic:

Limit the effect time, the bubble should function as an effect with a timer shown in the inventory. I would suggest 5-10 seconds be the timer as this allows a player that has dived deeply and got themselves in a bad situtaion to have time to find air. Secondly the Octopus should have a cooldown or the player should have a cooldown depending if you want to balance mass amounts of Octopi. I would say 1-2 minute(s) would be a reasonable amount with per entity cooldown as the user would require a decent amount of octopi and at that point its less effort to get water breathing or a conduit. Thirdly I think a sound effect needs to be played when the player gets the effect or something besides a bubble around their head.