Mugly is the first boss appearing in Donkey Kong Country Returns who is an unknown species known by anyone currently. Mugly appears in the Jungle world where he can be seen eating some bananas until Kalimba hypnotizes him to attack Donkey and Diddy. Thugly appears to be the same species as Mugly and is likely to be Mugly's relative.
Mugly appears to be a banana shaped monster whom is yellow with red spikes on top on which he can let in and out. He also has red claws and can turn orange and red when hit enough times by Donkey and Diddy.
When starting the battle, Donkey and Diddy must jump on Mugly while he isn't spiked on the back at first after Mugly attempts to ram into Donkey and Diddy. Mugly also lets down his back spikes, giving the Kongs a chance to jump on him as an attack. Sometime, Mugly attempts to crush Donkey and Diddy by jumping high up into the air and landing down again. Donkey and Diddy can also roll into Mugly while not spiked as an attack.
Later in the battle, Mugly turns orange, then red and becomes more aggressive and fast. He also crushes the ground and tries to attack Donkey and Diddy with a shockwave attack.
When Donkey and Diddy manage to jump on Mugly nine times, Kalimba becomes revealed out of Mugly and injured and Donkey must punch Kalimba and knock him out. After he knocks him out, Donkey and Diddy can access the second world, Beach.