Loyal wizard pets similar in appearance to Jack Russell terriers
Crups fact file
Small terrier with a forked tail
Highly aggressive towards Muggles
Loyal to their wizard owners. Crups were bred in Williamsburg by President Thornton Harkaway, who resigned after his pets savaged some local No-Majs
The Crup is almost certainly a wizard-created dog, as it is intensely loyal to wizards and ferocious towards Muggles.
Fantastic Beasts and Where to Find Them
By J.K. Rowling