Exclusive skins
There are two types of exclusive skins in BoB. There are developer/user-exclusive skins and pre-release donor-exclusive skins.
Developer/User-exclusive Skins
The Sen Rex is a non-customizable Tyrannosaurus rex skin exclusive to the animator Senoba based off of her original character. Currently, it is the only user-exclusive skin in the game.
Donor-exclusive Skins
The bioluminescent megalo skin named "Glimmer" is a Megalosaurus skin available only to players who had donated the amount of money equivalent to the Mighty Megalosaurus donation tier ($70) or higher before the game's release.
The bioluminescent Apatosaurus skin is also currently in the game. However, due to being exclusive to the Amazing Apatosaurus donor tier ($2,800+) it is an extremely rare sight.
Currently, these are the only glowing skins in the game. In the future, glowing skins will be added for the dinosaurs every donor tier higher than Mighty Megalosaurus is named after, including (but not limited to) Acrocanthosaurus and T. rex.
The only way donor skins can be acquired by those who did not donate pre-release is by being nested by at least one parent with a glowing skin. If only one parent has the skin, the offspring has a 50% chance to inherit it. If both parents have the skin, then it is a 100% chance.