Stealth Buddy
Stealth Buddy is a BETA mascot. It can walk the page and the window, and move to the Windows desktop when the window is minimized. Mute commentary, pranks, and sounds separately. Size is adjustable.
Turn it on in Settings → AI. Buddy sounds (Grapple, Teleport, Laser Eyes, and the rest) are in Settings → Sounds.
BETA: Settings and the AI more menu label it as beta.