Honestly, when I saw the gif, I thought the cats had run across some ants/ant trails, causing that reaction.
As mentioned by others, cats/dogs/rodents like to roll around in the dirt (my outdoor cat does, also) but to have them all spontaneously do this behaviour at once, I thought was most likely due to ants. Ants release formic acid, and use formic acid in their scent trails, the smell of which causes cats to go a bit crazy. (Dead/crushed ants release a lot of the chemical, which serves as a warning for other ants, but also makes cats go nutters.)
The reaction of the cat in the lower-left-hand corner of the .gif has it shaking its head, as if reacting to the smell of the ants. At least that's my view of it. ^^