|Owner|| Eli Shane|
King of Sling
When transformed, the Slyren has the ears of a bat, frog-like arms, and a fishtail. It has a yellow-colored belly but it's mostly colored blue. Its tail and mohawk are colored turquoise.
- Protoform Abilities - Perimeter alarm, can mimic sounds.
- Whistleer - Flies rings around opponent, create a sustained, ear-splitting scream.
- Sleepytime - Strange trilling call puts opponent to sleep.
- Blammerang - High-speed sonic boom blast.
- HyperSonic - Creates a high pitched frequency that causes temporary deafness in an opponent.
- The Slyren is a play on "Siren". The Sirens are female sea monsters that originate from Greek mythology. The Sirens would sing and lure sailors to dangerous waters, which would lead to their deaths. Sirens are also a type of swamp dwelling legless amphibian.
- A Slyren can be seen among Twist's Slugs after revealing his alliance with Blakk.
- Only other Slugs are immune to their singing.
- A Slyren is the only Slug that can break a Geoshard's crystals.
- A Slyren's voice can affect Ghoul Slugs.
- One was seen being ghouled in "Dark as Night". Neither its Ghouled protoform or its velocimorph has been seen in the show, though.