Similar to a canker or a canker sore, a cankersaurus rex is incredibly painful and occurs in the most inconvenient areas of one's mouth.
I woke up this morning with a wicked canker sore on the tip of my tongue... but I accidentally chomped it midway through a delicious bite of Oreo O's. Now it's definitely a cankersaurus rex. Brutal.
A hardo is a person who tries extremely hard at everything. Most times a hardo will try very hard at things that do not require excessive effort. For example, sports practices, gym class, etc.
Wow did you see Jack at practice today? What a hardo!