Copper did this when he was still sick before we knew what was wrong with him, he would hide under the bed and come out with his mouth soaked and foamy. He also would wake me up in the night the same way
He was having siezures but it was really hard to tell that they were actual siezures. His system was overloaded with toxins. He hasn't done it since we changed his diet.
I guess that this wouldn't really apply to Uni but tht is the only time I have expierenced anything like it. I am interested in reading if other posters have to say.