War rat mask. This is a cannibal rat, trained specifically to hunt other rats.
The rat killer is repeatedly mentioned in fiction and in the press.
Such rats were bred under special conditions. A dozen rats were locked in a box and not fed.
After some time, there was only one, the strongest and most vicious rat left,
which survived by eating everyone else.
She increased significantly in size due to her diet and could only feed on other rats,
she did not accept any other food. This was the “rat killer”.
Of course, such a rat is a literary fiction.