The Red Dust by Murray Leinster

Burl fell headforemost upon the spongy top of a huge toadstool that split with the impact and let him through to the ground beneath, powdering him with its fine spores. He came to rest with his naked shoulder half-way through the yielding flesh of a mushroom-stalk, and lay there for a second, catching his breath to scream again.

Then he heard the whining buzz of his attempted prey. There was something wrong with the beetle. Burl's spear had struck it in an awkward spot, and it was rocketing upward in erratic flight that ended in a crash two or three hundreds yards away.