As to the Dry Ice "clue" it could be Super-Glide. This stuff is just like ice, but it's not cold, not wet, but it is slick. They used it on Viva La Bam and Monster House to make indoor skating rinks.
But... it weights a ton and costs alot so I doubt this would be used. A Sheet (36 sq. feet) is approx. $575.00 and weighs approx. 145 lbs.
Check it out!
Jay