Will Miss #153 - adult pajama costumes

On holidays and at festivals (and sometimes during sales at shops), I see people wearing a particular type of adult pajama costume. The one in the picture above is Stitch from Lilo and Stitch, but I've seen people wearing dragons, eggplants, and other weird things. I imagine there is some company in Japan that makes this particular kind of costume which resembles a baby's sleeper. I don't know if