How to prank a co-worker

A buddy of mine at work is none too pleased that I’ve taken on this new vegan-ish diet because once a year, we battle in a no-holds-barred body composition assessment. He already waved the white flag (though we measure in October), so to help him feel better the other day, I brought him a cup of syrupy shave ice. He humbly returned it and said it’s mine and I should eat it. I packaged it and brought it back saying it was a gift from a recent sponsor at our place of employment. He rejected that too. So the only responsible thing I could do is humiliate him semi-publicly.
Yes, it’s in the company refrigerator…

-Out of the Wilderness