There is probably just enough light to make this super creepy, and Rodolphus hasn't yet learned that he shouldn't be using magic the same way he uses magic in his own world. The ball of light that pops out of his wand is deliberately not very strong — why send a beacon to anything that might be out there? — but it brings a shivery level of detail to the flesh floating below.

That is not 'poking it' really but after a few moments he gestures and the ball extinguishes itself.