A conversation about how to kill an octopus (in the event that it has decided to wrap itself around your head and therefore more conventional means of inducing death such as a spear are not available) lead to the plural of octopus and then to the question of the term for a group of octopodes. I never managed to find the answer to that question, but we did run across some other interesting ones:
a smack of jellyfish, a business of ferrets, an intrigue of kittens (I call band name!), a carload of monkeys, a plague of locusts (geez, one time and that's what you're called forever), a fever of stingrays (apparently they need more cowbell), a mutation of thrush, a stare of owls. . .
they're all here.