Honestly, Strange, good call, because after a little unseen gong rings, the masseuses come out. It quickly becomes obvious why the floor is wet: they literally are giant snails, the rubbery 'foot' contracting and squeezing to push them along the floor. While they're not large enough to completely cover Lambert or Strange, they come pretty close, and they're definitely large enough to cover their back.

One waves its feelers at Strange, and the magic translation spell helpfully communicates:

"Good afternoon, sir. Before we begin, is there anything I should know? Injuries or anything that needs particular attention today?"