It's light that's manipulated artificially, a really narrow beam of it. You can get handheld stuff like pens and keychains that have a laser light on it - even specifically made for pets if you want - and it shines a red dot wherever you point it. Cats and dogs go crazy for it, like they're chasing a bug on the wall and floor that they can't catch.
I gotta go to the pet store, I'll grab you one so you can try it out.