Critter Fighters: TropiKILL Castaway is a spin off to Critter Fighters. It is released in August 2007 on the Wii, PS2, PSP and DS. The story is when the Small Gang try to uncover the legends of a forgotten island they've been washed up to by accident.
- Voo Dude: The mysterious masked tribes man of the island. He can take control of enemy's minds.
- Marine: An otter captian of a boat that sunk by the guardians. She can swim fast underwater.
- Sarah Mcromp: The Main Antagonist. She is a wealthy archeoligist mouse who is trying to uncover the curse of the island. In the end, she drowns in the flood with Nima.
- Nima: The Secondary Antagonist. She is a brown bat who Red has a crush on, but after it was revealled that she was working as Sarah's cohourt, he is heartbroken. In the end, she drowns in the flood with Sarah.
- Ancient Guardians: One of the 2 enemies in the game. They are ancient statues tyring to prevent anyone from unleashing the curse.
- Mouse Soldiers: One of the 2 enemies in the game. They work for Sarah Mcromp and Nima.
The Small Gang are on their boat, trying to have a nice summer vacation. Suddenly, a storm hits and everyone goes over board. Red then wakes up to find himself all alone, and explores the jungle to find his friends. He finds all his friends who are with a mysterious masked sage named Voo Dude, and they plan to make a signal to contact a ship. While collecting parts for their rescue beacon, the Small Gang meet a brown bat named Nima, who Red develops a romantic interest into. Nima then gives the gang a radio to contact a ship, much to their delight. However, when the ship arrives it gets attacked by mysterious statue creatures. The captian, Marine, escapes right before the ship sunk and she is stranded as well. Voo reveals that the statues are ancient guardians who's duty is to protect the island from the deep curse and they see anyone as a threat, even the ship.
With no ship, the gang will have to find another way to escape the island. Going deeper into the jungle, the gang explore temples where they encounter more guardians including giant entities. The gang later see Nima, only to realize she is working for an archeoligist mouse named Sarah Mcromp and she was actually trying to get them off the island. Sarah Mcromp has been trying to find the mystery of the island curse that was only found by a tree frog named Ugam 600 years ago, and now that the Small Gang learned too much about her plans she orders her Mouse Soldiers to kill them. The Small Gang managed to escape, and decide to stop Sarah and Nima from unleashing the curse. They pursue Sarah and Nima in the Guardian Temple, where Sarah manages to unleash the curse with a cursed entity leashing out. After the Small Gang destroy the entity, the curse gets sucked back in, causing the temple to collapse and be flooded by water. The eruption sends both Sarah and Nima falling into the flooded chasm, to their deaths. The Small Gang escaped the temple which collapsed completly, sealing the curse for good. Luckily, the destruction of the temple managed to attract a plane which drops by to rescue the Small Gang.
Before Red gets on the plane, Voo Dude takes off his mask and reveals that he is actually Ugam who was cursed to be immortal and given witch powers. On the plane ride home, Red waves goodbye to Ugam who stays on the island.
- There only 2 enemies in the game, making it the least amount of enemies in this series.
- The story in the game is very similiar to The Sims 2: Castaway, since it involves the cast being stranded on a mysterious island and trying to escape while exploring it's legendary landscapes.
- The first characters to die are Sarah Mcromp and Nima. Thus, TropiKILL Castaway is marked as the only Critter Fighters game where a character gets killed.