The crystal gem apple is a special apple that Tree Trunks really wished to taste. It first appears in the episode "Tree Trunks." It hangs in the middle of a mushroom-shaped tree deep in the Evil Forest and is protected by the Crystal Guardian. Whoever eats (or takes a bite out of) the Crystal Gem Apple is teleported to the Crystal Dimension and given ultimate power over the Crystal Men until the gem leaves their body. In the main dimension, where the Crystal Gem Apple grows, it may appear to bystanders that the consumer thereof spontaneously combusts, especially when the bystanders lack the knowledge of the power it possesses or of the Crystal Dimension from which it comes. The apple reappears in "Crystals Have Power" when Jake kicks Tree Trunks in the stomach and she coughs it up.
The Crystal gem apple appears to be a regular apple, only it is crystallized, making the apple look like a ruby. Although the apple is crystallized, the leaves of it appear to be normal.
- It seems when people eat it they get obsessed with crystal power and get transported into the Crystal Dimension.
- The apple doesn't seem to get digested, it seems to stay in someone's stomach until someone gets it out of them.
- The Crystal Gem Apple is a weapon in FusionFall (Thrown Type) found in the same dungeon as Stanley.
- In the episode "Tree Trunks," it is seen that Tree Trunks just takes a bite of the gem apple before being transported to the Crystal Dimension leaving most of the gem apple still hanging from the tree. In the episode "Crystals Have Power," however, it is shown on the flashback that she ate the entire gem apple.
- In the episode "Lady Rainicorn of the Crystal Dimension" a crystal sandwich is shown to have similar properties as it teleports the "eater" to the crystal dimension but does not give any extra power.