A non-heated blow dryer mounted on the floor with a mat in front that has a contact switch.

When the dog steps on it, the blower shoots cool air into the dogs face.

Why? Your dog will know why. (see link)
-- doctorremulac3, Dec 10 2014

Bowser Blast Canine Wind Toy Proof of Concept https://www.youtube...watch?v=Q7VHNc0sxKs
[doctorremulac3, Dec 10 2014]

Proof of concept 2 https://www.youtube...watch?v=1xwUzOge0oo
[doctorremulac3, Dec 10 2014]

random, halfbakery