*In her dimension, Gwen found the Omnitrix when it fell to Earth during the Tennysons' summer vacation in lieu of Ben.

Gwen 10 first appears in Alien X-Tinction, where she is brought to Dimension 27998.3 by Ben and Maximilian to help fight Alien X. Gwen transformed into Ripjaws tries to fight Alien X head-on, but is briefly defeated, having her fall cushioned by Ultimate Alien Ben as Ampfibian and being protected by Omniverse Ben as Bloxx.

Gwen eventually convinces everyone to fight Alien X at the time. As Ripjaws, Gwen is able to synchronize her powers with her counterparts and remove the alternate Omnitrix from Alien X. After Alien X is defeated, Gwen states that she doesn't like her enemy being an evil adult Ben. While Maximilian takes Ben X elsewhere, Gwen thanks the others, stating that they couldn't have beaten Alien X without her. She is last seen being pushing Omniverse Ben into the portal before returning to her home dimension.

Gwen is a bit more feisty than her counterpart in the reboot universe, willing to kick the alternate Bens if they irritate her. She was also arrogant & felt that the other Bens (especially the teen versions) wouldn't have been successful without her help.*