Based on the time of year this strange looking beetle was found, we believe it might be Meloe impressus. During April and May, you can find the similar looking Black Meloe (Meloe niger). As you might guess from their short-stubby wings, the adults are flightless ground-dwellers. With their comically bloated abdomens, it would be amazing if they were able to get off the ground even if they had larger wings. If handled and squeezed, they employ a chemical defense that will blister your skin …so better to observe and not touch.
Photo by Heather McKee around 10/4/20 near Clinton, MT