I think Chubb is being a bit too hard on himself. I mean yeah it's true had he not scored they could have run out the clock, but he didn't miss the PAT and he didn't give up an immediate 66 yard TD, an onsides kick, and then another TD. That was a total team failure the last 1:55 of the game.
It's Brownie the elf. He was one of the original mascots. Basically, Cleveland has a huge immigrant population, and this stemmed from an old german/polish fairy tale about a house elf who would help you do chores at night.