What is reskinning? Simply put it is when you take one creature and describe it differently. You leave the stats the same, so you can run it them same if you wish, but with the creature looking completely different you have a completely new creature.
Bugbears resemble hairy, feral goblins standing seven feet tall. They take their name from their noses and claws, which are similar to those of bears. Their claws are not long and sharp enough to be used as weapons, so bugbears often armor and arm themselves with a variety of purloined gear. Most often, this gear is second-rate and in poor repair.
Bugbear eyes are greenish white with red pupils, and their wedge-shaped ears rise from the tops of their heads. Most bugbears have hides ranging from light yellow to yellow brown and their thick, coarse hair ranges from brown to brick red.
Rhinox are large humanoid creatures who bear two horns on their sloped skulls. These horns however are not on either side of the head but in the center of their snouts. Their horns are kept a brilliant ivory white and are a great source of pride for the male Rhinox.
These fearsome creatures are stocky and are covered in a thick grey hide that provides the Rhinox with a natural sort of armor. While very intimidating these creatures are very stoic. It takes a lot to anger a Rhinox, but once they are angry they are a very dangerous foe. Those their legs are short and stocky for their size, they are very fast and even unarmed the Rhinox can use their horns for a powerful gore attack that can fell the sturdiest opponent.
While using the same stats of the Bugbear but describing it as above you create a brand new creature, and possibly a brand new race for your game world. You can also use the morning star stats that a typical Bugbear has (from 3.5) and use those stats for both their weapons and their gore attack.
If you have any suggestions for future Skin jobs, please leave them in the comments.