Tactics for the Swamp (Fortress).

The chance of a deadly strike for Gorgons is 10%. For every 10 Gorgons, they kill one creature (for example, 30 Gorgons will kill three creatures). If the number of Gorgons in the stack is not a multiple of 10, then for each creature, an additional 10% is added, which means they will kill one creature (it's easier to illustrate with an example... 34 Gorgons kill three creatures with a strike and, after the strike, have a 40% chance to kill not three, but four creatures).