The Mouse walks past Bitterbuck's cel. Nonchalant.

Pan with Mr. Jingles to find Bitterbuck, push in on Bitterbuck's face. Snorkel?
Var FPS on mouse

Plan A: No FX. All in Camera: Shoot Bitterbuck at compromise FPS or hide double speed FPS in camera move
Plan B: Two Element Comp w/Motion Control Track/Tilt/Pan/Focus & Variable Speed
Plan C: Cover in two cuts. No FX

(if using M/C)

1) Bitterbuck, no mouse
2) Mouse, no Bitterbuck