In short, yes.
A creature can take -20 on all of its grapple checks until its next turn in order to be considered not grappling. This allows it to attack other creatures while attempting to continue grappling the first. This is usually the best thing for large multi attack monsters to do when facing several opponents. Even if the creature fails to grapple, as long as its has the improved grab ability it is still dealing damage from its attack and can try again with its next attack. If the octopuss decides not to take the -20 and continues to grapple a single target, it has basically let go of the other targets.
If faced with a single enemy it may want to not take the -20 so that it has a much better chance of grappleing and then pinning its victim until it is dead.
A giant octopuss when facing 4 enemies take the -20 and attack each enemy twice. This allows the octopuss assuming it hits with each attack two chances of grappling the target. The target would take the tentacle damage from the two attacks and must succeed at two graaple checks or be grappled by the octopuss.
My question is if it wins both grapple checks against the same target, does the target take twice the constrict damage? (Constrict deals it damage with a successful grapple check) Or is constrict a yes or no condition?
Another question is can the octopuss make all 8 of its attacks before deciding who it wants to start a grapple with?
