Octopus (CR 1)

Small Animal (Aquatic)
Alignment: Always neutral
Initiative: +3 (Dex); Senses: low-light vision, Listen +2, and Spot +5

AC: 16 (+1 size, +3 Dex, +2 natural), touch 14, flat-footed 13
Hit Dice: 2d8 (9 hp)
Fort +3, Ref +6, Will +1
Speed: 20 ft., swim 30 ft.
Space: 5 ft./5 ft.
Base Attack +1; Grapple +2
Attack: Arms +5 melee
Full Attack: 8 arms +5 melee and bite +0 melee
Damage: Arms 0, bite 1d3
Special Attacks/Actions: Improved grab
Abilities: Str 12, Dex 17, Con 11, Int 2, Wis 12, Cha 3
Special Qualities: Ink cloud, jet
Feats: Weapon Finesse
Skills: Escape Artist +13, Hide +11, Listen +2, Spot +5, and Swim +9
Advancement: 3-6 HD (Medium-size); 7 HD (Large)
Climate/Terrain: Warm aquatic
Organization: Solitary
Treasure/Possessions: None

Source: Monster Manual

Improved Grab (Ex): To use this ability, the octopus must hit with its arms attack. If it gets a hold, it automatically deals bite damage each round the hold is maintained.

Ink Cloud (Ex): An octopus can emit a cloud of jet-black ink 10 feet high by 10 feet wide by 10 feet long once a minute as a free action. The cloud provides total concealment, which the octopus normally uses to escape a losing fight. Creatures within the cloud suffer the effects of total darkness.

Jet (Ex): An octopus can jet backward once a round as a double move action, at a speed of 200 feet.

Skills: An octopus can change colors, giving it a +4 racial bonus to Hide checks.

Aquatic Subtype

Creatures with the aquatic subtype always have swim speeds and thus can move in water without making Swim checks. An aquatic creature can breathe underwater. It cannot also breathe air unless it has the amphibious special quality.