Grimace's Birthday is an unlicensed Game Boy Color game that was commissioned by the McDonald's Corporation as part of their 2023 promotional event of celebrating one of their mascots' birthday. It is a short platformer that has skateboarding levels as a throwback to late-1990s pop culture and regular platforming levels. The story in the game has Grimace gathering a number of other McDonald's mascots for his birthday so they can watch him blow out the candles on his birthday cake. However, the candles have already been lit, so he must get all of his friends before the candles go out.
Watch this run played back on a Game Boy Player (via Swiss) here.