Large numbers of spider crabs normally don’t migrate to the south Australian coast until between May and July, but this year they arrived early.

The reason for the mass gathering of the crabs is the security their numbers give them as they molt. But things can get a bit tetchy on the march, as this footage, shot by diver PT Hirschfield on March 4, shows.

Hirschfield told Storyful, “I have filmed crabs getting together in the millions, all stacking up on top of each other and getting along fine. But it doesn’t take much when they are on the march to start a scuffle, and that can quickly escalate into a battle that both Marvel and George Lucas would be proud of. May the best crab win.” Credit: PT Hirschfield via Storyful