It is possible but it’s certainly near impossible to prove or disprove.

Any existence outside of our visible universe remains… well… unobservable.

As a result, any laws of physics that reside outside of it are unknown, and so is the possibility of a collision, if there even are other universes out there.

Even if one were possible, it would be impossible to know what effect it could have on our own, if any, as it would require us to know what sits on dimensions outside of our universe, and the laws of physics that reign there.