It reminds me of a dog shaking a stuffed animal. The intensity doesn't seem to correlate to the type of treat she's about to eat: what causes a frenzy one day will be wolfed down without fanfare the next. One of the first times she did this, I was holding her and she managed to whack me across the face with the cantaloupe. Excitable rodent.
Since then, I have been trying to video her doing this. All sorts of videos, all with lackluster performance. On a whim this morning, I picked up the camera before I gave her a slice of cantaloupe. Success!
Kill it, Pinni! Kill it!
What a goofy guinea pig.