Splitworm

From Blaseball Wiki

At first glance, a splitworm looks just like a normal worm. Unlike normal worms, they are an invasive species to the Core and replicate at absurd speeds. Slicing or otherwise splitting a splitworm in half creates two worms rather than destroying it. Though the number of splitworms created through this method is theoretically countable and always sums to the number of original splitworms, practical experience brings the number of splitworms in an infestation far too close to infinity for comfort. The JORMUNGANDR-CLASS WORM UNIFIER is built to consolidate splitworms and handle infestations. The rare instances where the JCWU breaks are certainly cause for concern.