I perma froze a boss

I forget the name of him, but the worm in my Trenches map last night bugged out. I had him near frozen and I believe as he was diving down, right next to the far right/bottom wall, he got stuck. Even after the debuff went away he was just stuck there doing nothing. If I got too close to the tail, that could hit me, but I ended up finishing the map because I could just attack and it just took the damage. One thing to note, it was difficult to actually target and hit him directly and had use the lighting arrows stuck in the ground to do damage. An easy fight normally, this turned it into a longer battle that was total cheese.

Maybe his room needs to be a bit bigger?