What is this? Is it edible?
If this is a volunteer, it most likely cross pollinated with another type of squash. Cultivars of plants that normally cross-pollinate- cucumber, muskmelon, squash, pumpkin, pepper, corn, basil, etc.- may produce off-types when planted the following year. Seeds saved from hybrid cultivars will not "come true" (resemble "mom") when planted out the following season.
This does not look like a patty pan squash but it may be a type of winter squash. We cannot say if it is edible.