He laughed when he had the idea.
He was still laughing as he strapped the plaster casts onto his feet.
Stomping around in the thick mud, he'd barely been able to contain his mirth. He could almost imagine the look on their faces, when they discovered his handiwork.
He'd been puzzled when he stumbled across the other set of footprints, larger and much deeper than the ones he was making.
Sitting here now in this foul-smelling cave, while the creature stared at him with an indecipherable, but almost human expression, the whole thing didn't seem nearly as funny any more.