Does an octopus’s ink serve any purpose besides darkening the water for camouflage from predators?

Standard procedure is for the octopus to squirt the ink, change its own color as camouflage, and simultaneously jet away under the inky murk’s cover.

While the ink does do a good job of this, it also holds a secret weapon that further facilitates an octopus’s escape.

The ink, even when diluted in the ocean, is poisonous to some creatures and has a stunning effect on others.

How poisonous is the ink? If an octopus in an aquarium released its ink, it would kill everything inside the glass walls—, including the octopus.