Clyde is one of the South Park elementary school students and has given several last names on the show: Goodman, Harris and Donovan.  We're gonna go with the last one as our official choice.

Clyde Quotes

Clyde: Hey what's going on?
Kyle: Tweek and Craig are gonna fight!
Clyde: Really? CoolIt's funny because Tweek and Craig both went home about 15 minutes ago.
Kyle: What?
Token: Yea, they left.

Mr. Mackey: Wh-wh-what you need to do, uh, Damien to be overly nice. See, n-no matter how mean the other kids are to you, just don't retaliate. Err, be passive, mmm'kay? That's what I taught the little British boy, Pip, an-and just look at how much the other children like him now!
(scene changes to the playground, a group of kids are gathered around Pip)
Clyde: I bet I could spit the most on him! (spits on his left shoulder
Bebe: Oh, yeah? I bet I could spit in his hair! (spits in his right eye)
Pip: Oh! Nice try! A little higher and you've got it!

South Park Quotes

Chinpokomon Executive: You are American.
South Park Toy Store Owner: Yes.
Chinpokomon Executive: Ohhh, you must have very big penis!
South Park Toy Store Owner: Excuse me, I was just asking you what your up to with these toys.
Chinpokomon Executive: Nothing, we are very simple people with very small penis. Mr. Hosik's penis is especially small!
Mr. Hosik: So small.
Chinpokomon Executive: We cannot achieve so much with such small penis, but you American wow, penis so big, so big penis!
South Park Toy Store Owner: Well aah I guess it is pretty good size.

James Cameron doesn't do what James Cameron does for James Cameron. James Cameron does what James Cameron does because James Cameron is James Cameron!

James Cameron