Here is a pic...

Really can't make out what damage there is in that photo. Can you zoom in on the actual stems that were eaten? Could be insects, slugs, turtles, or a furry rodent at this point.

Looking at the amount of damage, it's probably a deer.

Yeah, I'm not the best photographer, so I know it's hard to tell the amount of damage if you don't know what it looked like before. The back of the plant where the brown shoots are, are all stems. Whatever ate it, left just a tiny bit of foliage and a few flowers in the front where the green and pink is. I have a hosta to the right, hose, and weeds in the picture, so it's not the best. I will try to take a new one later on.

I'm also thinking it was maybe a deer due to the amount of damage. Begonias are supposedly "deer resistant." The deer near my house must be starving because they seem to eat all kinds of stuff.