Bop is the host of the show. Unlike most of the characters, they aren't represented by an item, and can really only be compared to an Oval if anything. They are odd about their actions, having what can come off as no limit to what they can do. Their most common abilities include mass summoning and manipulation of things like Pins, Thumbtacks, and beans, though he also makes use of two larger scale summons: The "Oh No Omatone", a way to project his voice for announcements (or just be loud in general), and the "Bop It Blaster", a large, devastating beam that originates from a large, floating Bop-it game. They are as goofy as they come, doing little dances, not always making sense, but always keeping their signature smile on their face.
Bop's voice is up to interpretation, but were looking for something way out there and just... goofy. Take a look at his face and just do what voice you come up with from that.
(Side note - I (Zavemann) will likely end up voicing this character anyways, but this call is here juuuust in case someone else can do this better than I can).