She is tomboyish. She had the skates since she was born. She likes playing with Jack and is stronger than Jack. In the episode Sitcom and The Laugh Box, she was angry with Jack and destroy some things in Oggy's house. She also never cries like Olivia or Oggy. In Season 3, she wears a pink skirt and pink Mary Janes.
Monica looks like Oggy since they are twins. She has blue fur lighter than Oggy’s, a red nose, blonde hair, pink eyes, light pink tummy, white gloves, and pink roller skates with green lines on them. She also has an oblong shaped tail. Her daughter, Jack and Monica's Kitten, looks like her mother but looks more like Jack.
- Love & Kisses (First Appearance)
- Go For It, Jack!
- Soldier for a Day (Frame)
- Don't Rock the Cradle!
- Sky Diving
- Oggy Is Getting Married! (cameo)
- Oggy the Babysitter
- Extreme Indoor Sports
- The Power of Love
- Freefall Jump
- Sharing Oggy
- The Laugh Box
- The Giant Roaches (cameo) (Last Appearance)
- In Extreme Indoor Sports, Monica uses fly swatter for the first time to swat the cockroaches at the end.
- She had the roller skates since she was born.
- Her phone number is +444 333 222. Her name also seen when she gave Jack her number as she leaves.
- She also appears in the flash game "Oggy's Whack Them All".
- With the exception of certain parts, Monica is mostly absent in Season 4 and Season 6 (Due to most of the episodes being remastered of the first two seasons). She also never appear in Season 1 and Season 5.
- She is seen with long legs in a picture in Soldier for a Day from Season 2.
- In some episodes in Season 2, she wears pink rollerskates. Her eyes looks normal and her two pony tails have no bows shown tied to it.
- In Deep Trouble and Formula 1 (Remastered Only), she looks different than her most appearances in Season 3. She wears a pink skirt and no rollerskates. Instead, she wears pink shoes and her eyes irregularly shaped, similar to Oggy's eyes sometimes. Also, her nose is irregularly shaped, similar to Oggy's nose.
- In Oggy Is Getting Married!, she seems to be fat because her body is irregularly shaped. and her nose is irregularly shaped, similar to Olivia's Nose.