Lobster Mushroom (Hypomyces lactifluorum)

What it actually is

Hypomyces lactifluorum isn't a mushroom species. Per the Missouri Department of Conservation field guide, it's a parasitic fungus that infects certain white-spored Lactarius or Russula species, coating them in a vivid orange to orange-red, finely bumpy crust and reshaping the host into a contorted, capped form as it grows, often appearing as humps on the forest floor from July through October in mixed woods. Cut open, the interior is pure white.

The partial-coverage safety check

Because Hypomyces lactifluorum transforms whatever mushroom it infects, and some of its hosts (certain Russula and Lactarius species) are not edible on their own, the standard field-guide precaution is to only harvest specimens where the orange crust has fully coated the mushroom, with no bare cap, gills, or pores visible anywhere on the specimen, per identification sources on Hypomyces lactifluorum. A partially coated specimen doesn't give a forager enough information to identify what species is underneath.

Per the Missouri Department of Conservation, general foraging caution applies here as with any wild mushroom: be certain of the identification, and eat only a small amount the first time to check for a reaction. For dangerous lookalike pairs among other species, see the Dangerous vs. Edible Mushrooms guide.