"Do you want to build a monster?" sounds excellent. Personally I find it more tempting that snowman-building.

Apparently "Let It Go" is so much an ear-worm than my 15-month old nephew, a child who can basically say mummy, daddy, and duck, can nonetheless whirl his arms wildly while slurring the tune. It's probably some sort of alien meme, and one day a critical mass of the population will know it and Cthulhu will arise.