‘Onygena corvina’ seems like a good candidate for the mushroom death project. Here is a description from “Mushrooms of the Pacific Northwest: Timber Press Field Guide”
“Onygena corvina- Albertini and Schweinitz
Small mushroom structures with a cap and stipe are found in several groups of ascomycetes, for example, the fruitbodies of Cordyceps, Vibrissea, and Mitrula, and the club-shaped earth-tongues. Though similar in appearance to these fungi, the very small fruitbodies of Onygena species differ in that the cap surface breaks into a powdery spore mass at maturity. The two most common species are O. corvina, which occurs on owl pellets, bird carcasses, hair, and wool, and O. equina, found on the decaying horns and hooves of cattle and sheep. Onygena corvina reaches at most 2.5 cm (1 in.) in height, and has a whitish stalk and an ocher to light brown cap. These fungi are widely distributed but infrequently collected because of their small size and occurrence on animal remains, which are avoided by most mushroomers.