|“This meeting is a trap! A treacherous Munce ambush!”|
|— Groko, "Grief-Bringer"|
Groko is a member of the Geckles.
Groko was one of the Geckles collecting Moss Milk when he fell lost his balance from the ladder. His milk landed on Kai, revealing him and Zane. The Geckles believe they work for the Skull Sorcerer, and decided to take them to Gulch.
Groko and the other Geckles then agree to allow Kai to become their new leader and he gives out their plans such as defeating the Skull Sorcerer and uniting the Geckles with the Munce.
Groko is one of the Geckles who doesn't agree in a meeting with the Munce as he comments about the truce meeting being a trap. They decide to settle the matter by performing a slug race. Groko cheers for the slug which wouldn't allow the meeting, but is disappointed when the other slug wins.
The Geckles head to the truce meeting, but they stare down their rivals upon meeting them. When the ninja are able to calm everyone down, they all run away after hearing the sound of Grief-Bringer.
Groko and everyone else take refuge at the Geckle Strong-Cave. The Geckles realize they are also with the Munce and tension rises between the two tribes. Nya discovers a possible exit and requires everyone to work together to move the rocks. After realizing there is no way out, the Geckles and Munce make peace with each other and unite.
The Skull Sorcerer arrives and the ninja surrender themselves in exchange for the Geckles and Munce to remain free. However, the Skull Sorcerer lies and everyone is captured.