The Tongue Monster (dubbed as, "The Dirty Tongue Flapper" by Peridot) is a corrupted Gem that first appeared in "Kindergarten Kid". Throughout the episode she was chased down by Steven and Peridot, finally being poofed and bubbled by Peridot.
The Tongue Monster is a bipedal, vaguely avian creature with two long dark green legs which lead into an orb-shaped body covered in shaggy teal fur. On either side of her head are a set of three small eyes with pale green sclera and lime-green irises. She has a large mouth with fang-like teeth and a set of three dark green tongues she often undulates when vocalizing. Her gem is located on the center of her nose and appears to be iridescent, refracting various shades of gray, blue-green and brown on each facet.
The Tongue Monster was the main antagonistic force in the episode. She was left in the Beta Kindergarten after Jasper had been corrupted and poofed as a remnant of her army which was being rounded up by the Crystal Gems. When Pearl, Garnet, and Amethyst were incapable of capturing her, Peridot and Steven went out to hunt her down. Peridot attempted to outsmart her with her various "Peri-plans"; however, despite her and Steven's best efforts, the Tongue Monster managed to cause each of their plans to backfire. Steven then suggested that Peridot should think like the Tongue Monster. Eventually, Peridot and the Tongue Monster fell off a cliff, which Peridot survived due to her innate durability, while the Tongue Monster was poofed by the force of the fall. Peridot then bubbled her gem which end up being sent to the Barn instead of the Burning Room as Peridot considers the barn to be her home.
- Enhanced Speed: She can run at extremely high speeds, making her immensely difficult to capture, even when trying to grab onto her such as when Amethyst latched onto her using her whip.
- Enhanced Strength: She's capable of towing Gems like Amethyst and Peridot behind her while still running at maximum speed, and was easily able to lunge onto Steven and attack him using her talons.
- Intelligence: She was capable of outsmarting Peridot and Steven's plans, and then inadvertently caused Peridot to get crushed by a massive boulder through her curiosity.
|1. "Kindergarten Kid":||Debut||14. "The Zoo":||Absent|
|2. "Know Your Fusion":||Absent||15. "That Will Be All":||Absent|
|3. "Buddy's Book":||Absent||16. "The New Crystal Gems":||Absent|
|4. "Mindful Education":||Absent||17. "Storm in the Room":||Absent|
|5. "Future Boy Zoltron":||Absent||18. "Rocknaldo":||Absent|
|6. "Last One Out of Beach City":||Absent||19. "Tiger Philanthropist":||Absent|
|7. "Onion Gang":||Absent||20. "Room for Ruby":||Absent|
|8/9. "Gem Harvest":||Absent||21. "Lion 4: Alternate Ending":||Absent|
|10. "Three Gems and a Baby":||Absent||22. "Doug Out":||Absent|
|11. "Steven's Dream":||Absent||23. "The Good Lars":||Absent|
|12. "Adventures in Light Distortion":||Absent||24. "Are You My Dad?":||Absent|
|13. "Gem Heist":||Absent||25. "I Am My Mom":||Absent|
- The Tongue Monster's squared gemstone bears a striking resemblance to that of a Zircon.
- She resembles the small figurine Steven had in his room which he showed to Holo-Pearl in the episode "Steven the Sword Fighter", which in turn parodied Sonic the Hedgehog, who is also known for his remarkable speed.
- She, the Cluster and the bubbled Cluster Gems in Yellow Diamond's room are the only known bubbled Gems not in the Burning Room.
- However, in the episode "Change Your Mind", she presumably got released from the bubble and uncorrupted, alongside the other corrupted Gems.
- She parodies a well-known Looney Tunes character, the Road Runner, who was known for his antics alongside Wile E. Coyote.
- Like the Road Runner, she has avian-like characteristics, high speed, and also makes gurgling sounds.
- . She was the first and only gem Peridot has bubbled in the series.
|The Tongue Monster's gemstone is located at her nose. It is square and angular, having multiple asymmetrical facets and being in an array of dull colors.|