AppearanceAt first, Mugly is a yellow dinosaur-like monster. The boss walks on all fours and has a huge mouth with many white, sharp teeth. Mugly has two lazy eyes as well. The boss is covered with red spikes that he can retract at will. During Mugly's second stage, he is orange instead of yellow and becomes slightly larger. In his third and final stage, Mugly turns from orange to red.
Mugly has only four attacks. His most basic attack is just basically running across the screen back and forth. During this time, his spikes are retracted, which gives the Kongs (Donkey Kong and Diddy Kong) a chance to jump on him. Mugly can also jump along the stage, trying to crush the Kongs beneath him. During Mugly's second stage, he can jump high in the air and create a huge shockwave when he lands. Also during Mugly's second and third stage, he can charge with EXTREME SPEED at the Kongs, however, this can be easily jumped over. This causes Mugly to run into the wall and become dizzy for a while. During each stage, he attacks and performs faster.
To defeat Mugly, all the Kongs must do is jump on his back when his spikes are retracted. The Kongs must do this three times to defeat the boss for good. When Mugly runs across the stage, the Kongs have a good chance to jump on the boss's back. When Mugly jumps and tries to land on the Kongs, the Kongs can easily roll under Mugly and strike him on his back. Another good chance to jump on the boss's back is when Mugly charges for the Kongs, misses, and hits the wall. The boss will be unconscious for a short while, giving the Kongs are chance to jump on his back.
- According to the Prima guide, Mugly is related to Thugly.
- In 2-player Co-op mode, if Diddy Kong fires enough peanuts at Mugly or Thugly, they will retract their armor and eat the peanuts.