Is this safe?

I just go a crocodile bubbler and its mouth opens and closes. Could this cause any potential harm to my axolotl?

how big is your axolotl and how far does the mouth of your decor open? I dont think it would be a big deal, honestly the axie might even be a little afraid of it at first... I would monitor for a while and see how the axolotl is behaving, if he is trying to stick his head in the decor's mouth then yeah maybe remove it or put it somewhere harder to reach, even then i still think its doubtful because those "real water motion" decors are pretty lose, they move up with the bubbles and down with the lack of bubbles shouldnt be anything thats going to crush or harm your axolotl.

The only thing i would recommend would be to keep the bubbles to a minimum unless you have a fairly large tank, I actually just got an air pump and decor for my fish tank just couple hours ago and its pretty powerful so just make sure it doesnt create too much current or water agitation. Axolotls tend to not like that too much.

Seeing as axies will investigate anything that moves I wouldn't.
Bubblers aren't essential for axies, and if you want a crocodile thing then a polyresin skull is great.

I had to hide my air stone under the filter, in the very back corner of the tank, and they still manage to wedge themselves in there! Cheeky little devils they are

I ended up having to take it out of his tank because he spent almost the whole day in one of his hides that is the farthest away from the crocodile. I went out and got a smaller airstone that connects to the bottom of the tank instead and he is fine with that one (he even balances on top of it so the bubbles go all over his belly).