After returning to Winna Hazzard with the corrupted cat, you must talk to the pet to continue the quest. Until you do this, Winna will have a gray question mark above her head.

Also, be quick about talking to the cat. Once you are close enough to Winna Hazzard, the cat stops and no longer follows you. The cat will despawn quickly so be sure to talk to it quickly otherwise you'll be doing the whole thing over again.

The Hand of Dagun

Ancient texts claim that claws of Dagun excrete a poison that does not kill his prey, but mutates it into something else -- a member of the old races. Its value to us is unquestioned.

Dagun lives in the deep sea, but is regularly enticed to the surface by a tribe of Mirefin Murlocs in Dustwallow Marsh. Their oracles summon him with an enchanted sea kelp. If you kill enough oracles you'll find the kelp. Then place it on the Murloc altar, and Dagun will come.