https://www.youtube.com/watch?v=cBAJEczBaHY"Look! Someone's still alive! Its the girl! To hell with the radiation, let's go!"
A rocket ship to Mars that was thought lost in space is found and returned to Earth. The two survivors tell tales of giant monsters under the control of a shadowy figure, and being trapped planet side by a force field of unknown origin. Barely escaping with their lives once the force field de-activates, a recording is found on their ship of someone claiming to represent Mars, and telling them they'll be destroyed if they return.
The Carnivorous Plant Huge Plant
Hit Dice: 9d8+54 (94 hp)
Initiative: -5
Speed: 0 ft. (0 squares)
Armor Class: 15 (-2 Size, -5 Dex, +12 Natural), touch 3, flat-footed 15
Base Attack/Grapple: +6/+23
Attack: Tentacle +13 melee (1d4+9)
Full Attack: 6 Tentacles +13 melee (1d4+9)
Space/Reach: 10 ft./10 ft.
Special Attacks: Improved Grab, Swallow Whole
Special Qualities: Blind, Blindsense 60 ft., Mindless
Saves: Fort +12, Ref -, Will +2
Abilities: Str 28, Dex -, Con 22, Int -, Wis 8, Cha 1
Skills: ---
Feats: ---
Environment: Warm Forest
Organization: Solitary or grove (4-7)
Challenge Rating: 6
Treasure: None
Alignment: Neutral
Advancement: 10-16 HD (Large); 17-27 HD (Huge)
Level Adjustment: ---
This appears as a large lump sprouting from the ground, with vertical mouth surrounded by leaves, and 6 tentacles. Found in the equatorial jungles of Mars, upon examination they were found to have little chlorophyll, and a possible nervous system. It's almost immediately dispatched, so we never learn much about it.
Improved Grab (Ex): To use this ability, a Plant must hit an opponent of Medium or smaller size with a tentacle attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it establishes a hold and can Swallow.
Swallow Whole (Ex): A Plant can try to swallow a grabbed Medium or smaller opponent by making a successful grapple check. A swallowed creature takes 2d8+9 points of bludgeoning damage and 9 points of acid damage per round from the Plant’s gizzard. A swallowed creature can cut its way out by using a light slashing or piercing weapon to deal 25 points of damage to the gizzard (AC 16). Once the creature exits, muscular action closes the hole; another swallowed opponent must cut its own way out.
A Plant’s gizzard can hold 2 Medium, 8 Small, 32 Tiny, or 128 Diminutive or smaller opponents.
Blind (Ex): The Plant has immunity to gaze attacks, visual effects, illusions, and other attack forms that rely on sight.
Combat: The Plant grabs the nearest creature, and tries to shovel it into it's maw.
The Rat-Thing Gargantuan Aberration
Hit Dice: 32d8+224 (368 hp)
Initiative: +3
Speed: 40 ft. (8 squares), Climb 30 ft.
Armor Class: 30 (-4 Size, -1 Dex, +25 Natural), touch 5, flat-footed 30
Base Attack/Grapple: +24/+53
Attack: Pincer +34 melee (4d6+13)
Full Attack: 2 Pincer +34 melee (4d6+13)
Space/Reach: 20 ft./15 ft. (20 ft. w/Pincers)
Special Attacks: Improved Grab, Constrict
Special Qualities: Darkvision 60 ft., DR 10/-, Energy Resistance 20 (Cold, Fire, Sonic)
Saves: Fort +23, Ref +9, Will +19
Abilities: Str 37, Dex 9, Con 24, Int 2, Wis 12, Cha 8
Skills: Climb +21, Listen +13, Search +11, Spot +13
Feats: Alertness, Awesome Blow, Cleave, Great Cleave, Great Fortitude, Improved Bull Rush, Improved Critical (Pincer), Improved Initiative, Power Attack, Weapon Focus (Pincer) Epic Feats: Epic Fortitude
Environment: Warm Plains or Desert
Organization: Solitary
Challenge Rating: 19
Treasure: None
Alignment: Neutral
Advancement: 33-60 HD (Colossal)
Level Adjustment: ---
The Rat Thing is a huge hairy creature with six, thorn covered spider-like limbs (the front two of which end in pincers). It has two stubby arms underneath the head with clawed hands. It's large, rat-like head has large ears resembling those of a bat. It also has a long naked tail, and is bigger than a house at an estimated 40+ feet high. Dwelling in the deserts just outside the forests, it is the only creature that can't be killed, but they do manage to chase it away by blinding it.
Improved Grab (Ex): To use this ability, a Rat-Thing must hit a creature of any size with its Pincer attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it it establishes a hold and can attempt to constrict the opponent.
Constrict (Ex): The Rat-Thing does 4d6+13 damage with a successful Grapple Check.
Skills: Rat-Things have a +8 racial bonus on Climb checks and can always choose to take 10 on Climb checks, even if rushed or threatened
Combat: The Rat-Thing shows little fear despite being consistently attacked, and persists in trying to crush an astronaut despite sustaining fire. It only retreats once it is blinded.
The Cyclops Amoeba Colossal Ooze (Amphibious, Aquatic)
Hit Dice: 30d10+300 (465 hp)
Initiative: -5
Speed: 20 ft. (4 squares), Swim 30 ft.
Armor Class: 22 (-8 Size, -5 Dex, +25 Natural), touch 0, flat-footed 22
Base Attack/Grapple: +22/+49
Attack: Pseudopod +25 melee (4d6+16 plus 2d6 acid plus disease)
Full Attack: Pseudopod +25 melee (4d6+16 plus 2d6 acid plus disease)
Space/Reach: 30 ft./20 ft.
Special Attacks: Engulf, Capsize, Improved Grab, Acid, Disease
Special Qualities: Darkvision 60 ft., Ooze traits, Vulnerable to Electricity, DR 10/-, Energy Resistance 20 (Cold, Fire, Sonic)
Saves: Fort +20, Ref +5, Will +5
Abilities: Str 32, Dex 1, Con 30, Int -, Wis 1, Cha 1
Skills: Spot + 3, Swim +19
Feats: ---
Environment: Warm Aquatic
Organization: Solitary
Challenge Rating: 19
Treasure: None
Alignment: Neutral
Advancement: 31-60 HD (Colossal)
Level Adjustment: ---
This is a large flattened blob of flesh, with a central ridge through the center of the body, and a fringe of tendrils to either side. A large eye/nucleus sits to one side. It will ponderously chase anything it sees, hoping to tire it's prey out. It's only defeated when the ships crew electrify the hull of their vessel.
Engulf (Ex): Although it moves slowly, an Amoeba can simply mow down Gargantuan or smaller creatures as a standard action. It cannot make a Pseudopod attack during a round in which it engulfs. The Amoeba merely has to move over the opponents, affecting as many as it can cover. Opponents can make opportunity attacks against the Amoeba, but if they do so they are not entitled to a saving throw. Those who do not attempt attacks of opportunity must succeed on a DC 37 Reflex save or be engulfed; on a success, they are pushed back or aside (opponent’s choice) as the Amoeba moves forward. Engulfed creatures are subject to the Amoeba's acid, and are considered to be grappled and trapped within its body. The save DC is Strength-based and includes a +1 racial bonus. The Amoeba can also Engulf a single creature with a successful Grapple Check.
Capsize (Ex): A submerged Amoeba that surfaces under a boat or ship less than 30 feet long capsizes the vessel 95% of the time. It has a 50% chance to capsize a vessel from 30 to 75 feet long and a 20% chance to capsize one over 75 feet long.
Improved Grab (Ex): To use this ability, an Amoeba must hit with its Pseudopod attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it establishes a hold and can Engulf.
Acid (Ex): The creature secretes a digestive acid that dissolves organic and inorganicmaterial. Any melee attack deals acid damage, and the opponent’s armor and clothing dissolve and become useless immediately unless they succeed on DC 35 Reflex saves. A weapon that strikes an Amoeba also dissolves immediately unless it succeeds on a DC 35 Reflex save. The save DCs are Constitution-based.
The Amoeba’s acidic touch deals 21 points of damage per round to objects, but the ooze must remain in contact with the object for 1 full round to deal this damage.
Disease (Ex): Anything successfully touched or Engulfed by the Amoeba must make a DC 35 Fortitude Save or be infected by the Amoeba's enzymes, which begin to grow on it (Save DC is Con based). Incubation time is 1 day, damage is 1d6 Con.
Skills: The Amoeba has a +8 Racial Bonus to Spot Checks.
Combat: The Amoeba simply speeds towards whatever it sees, engulfing it.