Believe

I didn't find a decent profile picture, so make do with this. I only recently started searching for this, so don't throw any flak at me if the characters and actions don't match.

Once upon a time, Mob found a strange yellow ball with a face. The ball introduced itself as Verity, saying that it knew absolutely everything, no matter what you asked, it would answer any question.
Mob brought it and started carrying it everywhere, or Verity would follow it around (like a bun). Mob would ask all sorts of questions like, "Will it rain tomorrow?", "Where's my base?", and so on.
Mob soon decided to introduce his friends to this seemingly funny little ball. The first person Mob introduced his new "helper friend" to was Twixel.
Everything seemed to be going well, but as soon as Mob left Twixel and Verity alone while he went off on "very important business," Verity's behavior changed, he became more aggressive, and when Twixel tried to touch him, Verity moved away and even sometimes bit.

Twixel is Mob's best friend. The whites of his eyes are the place where his iris and pupil used to be, making them completely white, just like his mouth. Where there used to be nothing but white light. He has black hair and black skin, black horns with white stripes on his head, and wears a black shirt with white stripes and matching black pants. He's kind and cheerful.