Giant sensory bag "water bed." This is the best outside toy ever! Under $10 for a whole day of outside fun. Buy a 100' tarp roll from Walmart and duct tape, tarp roll comes in 10' sections that are perforated. She made two 40x10' sections and then folded them into a 20 x10 section. All perforations are taped. All edges of 20 x 10 section are taped, but leave small hole in one corner for hose. Don't let anyone walk on while it's filling. It is like a big water bed. Works best on flat ground.