When an Octopus is threatened by a predator it will squirt ink, change skin color as camouflage, and jet away.
As good a job as the ink does of hiding something as hard to hide as an octopus, it’s also poisonous to some creatures and stuns others, even when diluted in the vastness of the ocean.
How poisonous is the ink? If released by an octopus caged in an aquarium, the ink would kill everything inside the glass walls, including the octopus itself.
Most octopuses have no internal or external skeleton, allowing them to squeeze through tight places and escape.
They are also highly intelligent for an invertebrate.