From ErfWiki

A peep is a marshmallow candy made in the shape of a holiday icon, such as bunnies (Easter), pumpkins (Hallowe'en), hearts (Valentine's), and stars (Christmas).^[1]

In the comic, the only relevant shape is the chick, which is made for Easter. Parson indicates an enjoyment of the candy; however, his preference is to eat it in July, after it has had time to go stale.^Erf-b1-p015 This shape is used as the form for a gwiffon^Erf-b1-p007. Stanley, when participating in the summoning of the Perfect Warlord, requests that the person Wanda summons "snacks on gwiffons"^Erf-b1-p017, and oddly enough, he gets what he asks for.

[edit] References

1. ^ Peeps on Wikipedia