I think they are only frisky in certain circumstances. Like in electric storms, perhaps?
They were all at the apex of the tippiest toppiest leaf they could find...and they were fully stretched out with their eye stalks stretched to the utmost, waving their upper bodies around in a frenzied manner...for snails. Some were exchanging bodily fluids.
never seen anything quite like it.
Probably an omen, like the terrible signs of doom in Macbeth...you know, horses eating each other in the stables, a comet, snails becoming frenzied and not eating plants...