Monobeast

The monobeast is a vermin which detaches from a Patient suffering from Monobrow. It then moves independently throughout your hospital. When you mouse over a monobeast, the cursor becomes a targeting reticle. You may then exterminate the monobeast, so that a Janitor may dispose of its remains.

Superbug
In The Superbug Initiative there is a Hair Removal project that rewards the Browbeater item. These can placed in hospital to attract and trap monobeasts humanly.

Trivia

 * Shooting monobeasts is a reference to Two-Point Hospital's spiritual predecessor, Theme Hospital. In Theme Hospital, you could shoot rats that infested your hospital when hygiene became too low.