The Greenlight Pillow is a pillow obtainable in the store/pillows page in PFS. It is a bright green pillow with green neon around it.
This pillow was advertised as a "nightlite pillow", or a pillow your child could use as a night light. Due to the fact that it was growing bright green, many children weren't able to sleep due to it. Eventually, the pillow was taken off shelves and a new version was made, with a much softer green. But, some children still have the old Greenlight Pillow, and use it in pillow fights.