What attacks the train? (Patreon)

The replicators are 100% attacking the train to get those sweet sweet resources.

They are also very smart. They have deliberately seeded the length of the tracks with highly aggressive, territorial mutated animals.

These animals will assault the train many times and inflict wear and tear, acting as disposable shock troops, before the alpha strike from the Replicators arrives.

so I need ideas for creatures and what weird powers they might have, as long as they're highly aggressive and territorial.