Pukis

Among the Latvians Estonians and Lithuanians of the Baltic States, Pukis or Puuk is the name given to household dragons. A Pukis takes on the form of a cat when it is upon the ground but becomes a dragon when it flies through the air. All Pukis have the tendency to be tricksters and they guard treasure in a fiercely exclusive way. This works as an advantage of the householder but against his neighbours.

John and Caitlin Matthews, The Element Encyclopaedia of Magical Creatures, 2013, Pukis, p 376