When an octopus latches on to a human arm it likes, it can take some persuasion to get it to relinquish its prize. That's the lesson one Australian diver learned while out snorkelling for rock lobster in the waters off Perth recently.

"I stuck my arm into a small underwater cave and was surprised to have an octopus latch onto my arm with all its strength," he recalls.

Despite their soft, jelly-like quality, octopus suckers are really powerful. They're also extremely sensitive and capable of moving and grasping objects independently, which gives octopuses the dexterity to do some pretty nifty stuff – like open jars, use tools and make off with our GoPro cameras.

These creatures are also famously intelligent, and often appear extremely curious when faced with a new object – like a human arm. It's likely that a bit of this cephalopod curiosity was at play here.

"It wouldn't budge for a few minutes and several attempts at pulling it off were unsuccessful as it would just latch onto my other arm," says the Perth diver. "Eventually, it escaped to a seagrass bed with some probing."

It might seem counter-intuitive, but your best bet in a similarly sticky situation is to relax rather than struggle – just like this Canadian diver did when a giant Pacific octopus gave her an eight-armed face hug.