I have a two year old who has had diarea for about 8 days now, sometimes its really green other times it is really dark. I noticed that i had givin him grapes one evening and he had the grape skins in his stool. About 10 minutes after that stool he had went again and it was really dark and kinda clumpy like seaweed and had watery slimy stuff around it. I had givin him Watermelon the next day and about 2 hours later he had diarea again and it was dark green almost black with red from watermelon and the white watermelon seeds were there and also slimy. he has between 3-7 stools a day for the past 8 days. they are also very nasty smelling stools.