Grumpy Cropsies are the dirty and angry-looking ones, covered in purple slime.
If you make a match that includes a grumpy Cropsie, the whole match will turn grumpy and they won't count toward your target goal. So be careful!
Depending on the level you might be able to return the grumpy Cropsies back to normal with grass created using seeds and water droplets. The Clean-Up Grumpy Cropsies booster will also do the trick.
Turn those frowns upside down!