Gir

GIR is happy-go-lucky, enthusiastic, energetic, excitable, and extremely hyperactive, and will eat just about anything, regardless of whether it is edible or not. Most of the time he spouts nonsense, but does have a few, short moments of clarity: for instance, in "Walk for Your Lives" he actually contemplated whether making the explosion go faster would make things worse ("But if the big 'splody goes fast, won't it get all bad?"), and in "Bad, Bad Rubber Piggy" he questioned the wisdom of sending a machine into the past to destroy Dib.

Voice Reference- https://www.youtube.com/watch?v=oTSSRrn9RdY