You can loot this pet from the rare spawn Rotcap. Just like other Draenor rares he will be rare for the first kill and will only drop his loot for each character once.
Rotcap is located in the Spires of Arak – Draenor (cords 38.28)
Brillant Spore – Talents
As with all battle pets you will start out with the first talent and open the others as you level this pet. Talents will open at levels 2, 4, 10, 15, 20.