There are different enemies that you can encounter in VoidTrain.
Soldiers
Soldiers are enemies that you can meet in the Depots, Outposts and during Chases. They differ in armor, weaponry, and behavior. Their quantity and the type of weapons they use depend on your world rating, that is, on your progress in the game. You can learn more about them in the main article: Soldier.
Shark
Shark is a hostile creature that spawns in the Void after you leave the Depot. It can attack players or the train. While attacking the train it will be damaging objects like wooden floors and buildings near the place of its attack. The Shark can heal itself by eating fish or mutagens. If it eats enough mutagens it will mutate. More info on the Shark you can find in the main article.
Leech
Leech is a fish-like creature that can leave growth on the train's wheels and stop your train. They are hiding behind the rocks in the Void, waiting for the train. After they leave a growth, they disappear. Leeches can't attack and do damage to the player or to the train.
Pufferfish
Pufferfish is a hostile creature that is located on the Witch Islands. Thanks to its appearance, similar to the hook flowers, it hides among these flowers and only attacks if a player swims nearby or when it receives damage. If provoked, it will try to swim as close to the player as possible and explode, leaving behind a poisonous cloud. Explosion will deal some amount of damage once, but the poisonous cloud will damage over time.
The Swarm
The Swarm are a bug-like creatures that you will fight during the Arena trials. There are different types of bugs: Swarm Soldiers, Spitters, Bombers and Tanks. You can learn more about the Swarm in the main article.