Raiding with Leashes - Achievement - World of Warcraft
You'll get the cat that stands inside Naxxramas from doing this achivement called Mr. Bigglesworth(Mr. Bigglesworth - Item - World of Warcraft).
To earn this achivement you are required to learn all the non-combat pets that drops from Molten Core, Naxxramas, Blackwing Lair and Temple of Ahn'Qiray. These pets have a decent droprate and I've gotten atleast 1 pet each time I've done a whole raid. Molten Core, Blackwing Lair and Temple of Ahn'Qiray can be soloed but you'll need atleast a few people for Naxxramas because of Patchwerk and maybe a few other bosses depending on your class/spec.
There drops 3 pets from each raid, you don't have to do the last boss in any of the raids but keep in mind that there is still a few hard bosses you need to kill to get access to the bosses that drops the pets. I suggest to take atleast 1 person with you when going to Temple of Ahn'Qiray and atleast 2 persons to Naxxramas. For Ahn'Qiray you'll need a melee if you're a caster and a caster if you're melee to kill the Twin Emperors and for Naxx you'll need atleast 1 healer for Patchwerk since he hits really hard, it is duable as a blood dk but I suggest to take 2 persons with you as any other class/spec. Also a thing to keep in mind, you'll need frost damage to kill Viscidus in Temple of Ahn'Qiray. If you have no classes with frostspells in, you'll need either a Brunnhildar Harpoon, Brunnhildar Great Axe, Brunnhildar Bow, a weapon enchanted with Enchant Weapon - Deathfrost, or a weapon encoated with Frost Oil. If you can't aquire any of these and are over lvl 84 you can always get Enchant Weapon - Elemental Force - Spell - World of Warcraft.
Tips:
- You only need to learn the pets to get the achivement so you can buy them from the auction house or do them on your alts.
- As soon as you have learned the pet you can put it in a cage and trade it / put it on the auction house.