You and Beck broke up over your insecurity that he'd leave you for another girl, so it caused fights started by you.

You asked Tori for help and she suggested to get him something he's always wanted, and that's when you remembered he's always wanted a dog.

So you got him a dog and put it in his RV when suddenly the dog went angrily ballistic and there was a bunch of screaming in there, you thought it was beck until he walked around the corner in confusion, and unharmed.