Peter jumped and looked up, but he didn't recognise the stranger. Something else on his mind? Gosh I wonder what that could be...
He let out a deep explosive breath and closed his eyes, clearing his mind the same way he had learned to do while studying to be become an Animagus - it had taken months to get it right, though of course he hardly ever practiced, anymore...
"Wingardium Leviosa," he said, moving his wand with his left hand. The rock lifted again - he felt it even with his eyes closed - and he opened them again to guide it over to where he had wanted it to go originally. It was still wobbly, but at least he didn't drop it this time. "Thanks," he muttered, getting up and brushing sand off his trousers. He had to sheath his wand before he had a free hand to do this however, and he sighed inwardly. Everything was just so awkward. "Any first year could probably still do better, though. I'm just rubbish."