Hmmmm.... Tearing a hole through time and space..... Wouldn't that mean the universe would be ripped open and everything destroyed????
Maybe not if the tear immediately seals up on Nibbler once he's inside, thus everying in the universe remain not affected by it at all.
Edit I can see where your getting this from episode "Anthology of Interest I" "What-if Fry never came to the future?" Then the universe will be destroyed. But maybe not I have read a very good fan fiction about Leela going back in time to Fry's time from just about over the year 2999.
Now end my off topic talk.