Rocky
Drops from Macabre. The claws of a vulpin sharpen themselves naturally when walking around on any sort of cobblestone or rocky surface. Beast type. As I went around with a random group hitting all the spawn points when we arrived at the right spawn point random music started playing.
Rocky 
is a vulpin pet obtained by defeating the rare mob Macabre, which spawns in Ardenweald through a group dancing ritual at a Mysterious Mushroom Ring.
Guide awaiting review
Locate a Mushroom Ring
Travel to Ardenweald and search for a Mysterious Mushroom Ring, which appears at multiple spawn points including at 59.95, 29.4, at 36.50, 47.90, at 32.7, 44.77, at 57.93, 29.36, and at 47.91, 40.2. When you are nearby, you will hear music and see a rare mob marker on your minimap.
Gather Two Other Players
You need at least 3 players total to trigger the event — players from either faction can participate, so cross-faction groups work for this ritual.
Perform the Ring of Dance
Stand inside the Mysterious Mushroom Ring and have all three players /dance with each other in a chain: Player 1 dances with Player 2, Player 2 dances with Player 3, and Player 3 dances with Player 1. Once the chain is complete, Macabre will immediately spawn.
Defeat Macabre
Defeat Macabre, who is not a difficult fight. Any player who participates in killing Macabre can receive the Rocky pet — you do not need to have been one of the dancers to be eligible for the drop.
Tips
More spawn locations for the Mysterious Mushroom Ring are still being discovered beyond the currently known coordinates.
Rocky is also part of the Adventurer of Ardenweald achievement criteria.
