An octupus sprays black ink so the prey cannot see then the octopus runs away...
By camouflage . Blending into the same color as its surrounding makes it difficult for prey to seek out the octopus
it stinks ink
by making itself look like a venomous sea snake
They protect themselves by squirting ink.
A leaf tailed gecko would be an example of one such animal as would the mimic octopus.
baned
TANGA
It hides in the sand or campfloges it'self to look like a octopus
Primarily it hides and uses camouflage (the mimic octopus is a master at this) to avoid enemies. However when attacked, it will squirt a cloud of ink at its attacker, blinding and confusing it. Under cover of the ink cloud it will jet away from danger. Octopus also have a sharp beak that can inflict damage on an attacker and in one case (the blue ringed octopus of Australia), this beak can inject a poison into its attacker.
The octopus completely lacks any bones in its body.
how do young protect itself
A octopus doesn't make a shelter it make itself at home in human waste and caves.