Rocky

this one's quite an interesting one, because Rocky is the main monster of MMBTI, and is mute (for the most part wink wink)

so basically you will just have to do a bunch of ferocious ape sounds and either layer them together yourself or i'll do it for ya, so yeah, Rocky Rockford Rockleton III
(also his voice would have a mixture of ferocious ape and his original energetic normal male voice to it because during this time range he hadn't of snapped yet and I don't think kids would be very entertained by a monkey that sounds like a left for dead monster