Bo Sifus is one of Angry Grandpa's dogs. He first appeared in a vlog uploaded to the KidBehindACamera channel called GRANDPA'S NEW DOG!! (BRIDGETTE PRANK!), where Grandpa and Michael prank Bridgette into thinking that they are going to roast him for New Year's Eve's. Grandpa claims to have rescued him. He is now owned by Jennifer.
- Although they are not related, the brown spots on Bo's ears closely resemble those of Boo, Grandpa's other dog.