Writing's on the wall for this clever gender reveal

A couple decided to throw a truly unique gender reveal party by hurling water balloons at a wall to reveal the sex of their baby in Knoxville, Tennessee.

In video of the event we see the family gathered together and handed water balloons. Then they are instructed to throw the balloons at the wall, revealing a hidden message on the wall saying, "It's a boy! Sike! It's a girl!"

To accomplish this, a rain-activated spray product was used on the wall. Invisible when dry, messages and artwork are only displayed when the surface is 'rained' on.