Mr. Mittens (voiced by James Arnold Taylor) is a recurring antagonist and was Tim Burnout's cat while Albert is his butler. Mr. Mittens made his first appearance in 00-Johnny attempting to turn all of the citizens of Porkbelly into cats, but was foiled by Johnny and his friends.
As Tim described, Mr. Mittens was never a friendly cat, he despised his owner for never cleaning his litter box and all the dogs for chasing him. When Mr. Mittens became intelligent, he decided to turn all living creatures in Porkbelly into cats (with the exception for Albert, who he needs to stay human to clean out his litter box) with his Cat Zapper and "Turn Porkbelly into Catbelly". However, the zapper wasn't strong enough to turn humans into cats, so he invaded the military base and charged his zapper with their million-volts electricity source. The zapper was then set to create a wave to turn everyone in a 100-mile radius into cats in one minute, giving Albert and him time to escape. However, Mary and Susan, with the help of Johnny, Dukey, and the military, reverted the zapper in time to save the Porkbelly population from turning into cats. After the incident, however, Mr Mittens remained intelligent. His most common phrase is: "'''It is I, Mr. Mittens!'''"
- He was made intelligent with the same formula used to create Dukey.
- He is a member of the Johnny Stopping Evil Force 5.
- He constantly chokes on hairballs that Albert has to clean up.
- His female counterpart is named Madame Mittens. She was only seen in Johnny Alternative.