My favorite is Colorado’s cryptid, the Slide-Rock Bolter, which is basically a big whale-like thing with claws on its tail that it uses to hold onto the top of a mountain. Then whenever a miner or lumberjack is walking down below in a valley, it will let go and start sliding down the mountain, building up speed until it catches the person in its mouth and uses the momentum of its slide to bring it up the mountain on the other side of the valley. Then it will grab onto that mountain and wait for its next victim to appear down below.

Here’s a sketch I found online