This one was rather elusive for me too. After several unsuccessful attempts to camp the area with my main, I took an alliance DK there on another server and parked him there. Eventually got the pet by just checking each day before I logged in to my main.
What I did for pets like Tiny Bog Beast, Tiny Twister, Lofty Libram, etc. is check each morning where they spawn, fighting any that are up. Eventually you'll find a rare of each. I had a list of about 7-8 I needed and just thought of it as a daily quest.