Why Are You Green?

When we got home from the Homestead, we came inside the house and the cats were instantly swarming us. We keep dry food out for them all the time, but have been feeding them wet food in the evenings. They're both pretty thin and they really love it, so we figure no harm done. As I was shuffling through the door, both of the cats were stalking Jon. He went into the room where we keep their food, and two rooms away I hear him say "Why are you green??". I thought maybe the white one (Coconut) had rolled in some grass clippings, etc. but no, some wiseass dyed my cat green. WTF??!!