Trace fossils aren't always as exciting, but I like the ones I've found.
This looks like a burrow cast. From the "mottled member" of the Chinle Formation, Temple Mountain, San Rafael Swell, Utah, US.
Posting also to check my identification. My references indicate that the mottled member at this locale is known to have lungfish burrows ... unless they're crustacean burrows. This one seems large for a crawdad (even a Triassic crawdad) but small for a lungfish.