Gragg (ロッグ Roggu) and Glagg (グラッグ Guraggu) are two bosses from Wonder Boy in Monster World found at the end of the Jungle Temple. Together they are the second boss from the game, two rocks resembling demon heads. They fight Shion by releasing boulders from their mouths that roll down a ramp and they also fling little rocks like bullets. There is a little platform in the center of the room that can be used to avoid the rolling boulders.
- In The Dynastic Hero, Gragg and Glagg were replaced by two large rock turtles named Gang (ガンダ, Ganda in Japan) and Gong (ゴンガ, Gonga). They release the small rocks from their mouths and withdraw their heads to release the bolders from their shells.
- Gragg and Glagg are the same in Turma da Mônica na Terra dos Monstros, except that they were renamed as Pedra (Stone in Portuguese) and Pedro.
- The names Gragg and Glagg are derived from crag, and their Japanese names are derived from the words rock (ロック rokku) and crag (クラッグ kuraggu).
- While Gang and Gong have the same appearance in their artwork, their sprites are different.