As you can see, Octopus's arms have two rows of suckers.
These invertebrates eat a large variety of food like crabs, fish, scallops, and even other octopus. However octopus, have to go through many steps in order to kill their prey. They begin by grabbing onto their victim with their arms. On their arms are suckers which grip onto the prey. They then bites their prey with their hard beak located underneath their head and inject a poisonous saliva into them. Luckily, only the small blue-ringed octopus has the poison to kill humans. If their victim has a shell, they drill a hole into it so they can inject the poison into their bodies. After the poison has taken effect, the octopus finally eats their prey.