Anytime the players attack and do damage to the Octopus they must strike the body. Doing so requires that they either attack with ranged attacks or jump into the pool and attack.

Attacks against the tentacles automatically get capped at a minor wound regardless of the damage that is inflicted.

on a successful attack from the Octopus the target is restrained. The target can either spotlight and break free on a Strength or finesse roll of DC 15 or spend a stress to automatically break free.

If the Giant Octopus uses Pull and Submerge on a player: The player is Restrained and Submerged (under the water).
At the start of the player's turn, if they are still submerged and restrained, they take 1 Stress from the trauma of drowning and being crushed.
The player can use their turn to attempt to break free by making a DC 14 Instinct (Pull) check. Success breaks the Restrained condition.
If the player is not restrained but still submerged, they must immediately use a turn to make a DC 12 Instinct (Swim) check to surface (reaching the slick floor). Failure means they remain submerged and take 1 Stress at the start of their next turn.

Only usable while submerged or half-submerged. Creates a close range cloud of blinding ink. All creatures within the cloud must make a DC 12 Instinct (Focus) check or gain Vulnerability and cannot see anything until they leave the cloud.