"Oh, sure, Calvin! Give us a break!" -Ronald, about Calvin's "Invisible Cretinizer
Ronald is one of Calvin's classmates.
Although his only named appearance was in a regular strip as the test subject of Calvin's Invisible Cretinizer, he has made a few cameos, such as on the back of Homicidal Psycho Jungle Cat and in a Sunday Strip where Calvin pretends to be a dinosaur in class and gets stared at by several students, one of them being Ronald.