Cavall (also Cabal) was King Arthur's dog, used in the hunt for the great boar, Twrch Trwyth.
Cavall was Arthur's "favourite dog", and during a stag hunt, he was customarily the last dog to be let loose to chase after the game, according to Gereint.
Legend in antiquity has it that Cabal left his permanent footprint in the rock while pursuing the boar Troynt. The lore is preserved in the Wonders of Britain (De Mirabilibus Britanniae or Mirabilia in shorthand) appended to Historia Brittonum. The wondrous nature of this cairn of stones was that even if someone removed that foot-printed stone to another spot, it would be back at its original heap the next day.
Culhwch and Olwen names many dogs besides Cavall in the hunting party, and the quarry is no longer just the boar Twrch Trwyth itself, its seven offspring.
Or is he a horse?[]
Glas, Glesig, and Gleisad are referred to as dogs, and Call, Cuall, and Cavall as horses, and so on down the line in modern translations. However, in the first English translation by Lady Guest, Glas, etc. were construed as sword names and Call, Cuall, and Cavall were dogs.
A number of scholars seem to hit upon the similarity of the dog's name to the Latin word for "horse". In an article from 1936, R. J. Thomas said that "the name Cabal is from Latin caballus 'horse', which he considers a quite natural metaphor since the dog was strong and swift.
Bromwich further remarks, "Since carn means both 'hoof' and 'cairn' it seems more probable that Cabal/Cafall originally designated Arthur horse.. rather than his hound".