The Aquatic Relix Zone Boss, found in Aquatic Relix Zone, is the fourth boss in Sonic the Hedgehog Pocket Adventure. Rather than fighting Eggman in a machine as usual, the opponent is Knuckles. He has his standard attacks such as a punch, Spin Dash, and a glide. He uses the punch most often and uses the other two less frequently. The best time to hit him is in between punches and before he jumps. Curiously, the music played when you fight Knuckles is an 8-bit remix of the second act of Flying Battery Zone from Sonic and Knuckles, as opposed to the music that plays when he appears in Sonic and Knuckles and when you fight him in Hidden Palace Zone (which has a similar tile set to this part of Aquatic Relix Zone).