The other day me and an engineer friend of mine were hunting in the Varmint woods, we don't go too far in as we are in our 40s and 50s level wise. However after fighting in there for a little bit my and his pet started to attack for thousands of points of damage each time we hit the /pet attack macro. The screen would literally scroll with hits of 200, 150, 250, 175, etc...
We did this on a couple of mobs then thought we'd try a really hard one, and it worked on it too. The only drawback was that the mob didn't die right off, and we couldn't cast on it or attack it because it said that it was already dead. BUUUT, here's the really cool part, each time we did /pet follow, then /pet attack it RE-spammed all the attacks again. What this did for us is make the mob almost immoble it was moving so slowly. We knew a place where a Blaster Beetle hung out so we went over there and thought we'd try it on that since we could always run if things got bad, we knew the Blaster beetle would be moving like pond water and couldn't possibly catch us.
Needless to say at my level which at the time was 47th I got 10% of my level in xp every single kill. Here's the only drawback to the whole thing, the blaster beetle didn't die right off, so we had to re-summon a couple of pets each and keep sending in to kill it. BUT when we picked up aggro on the beetle it followed US at suuuuper slow speed while the pets ate its ass from behind, kinda like old Everquest Kiting. The cost in Engineer pets was easily reimbursed when we looted that critter, it dropped about 4k in cash, plus we both got 10% of our level in xp. It took a bit of random fighting before the pet (my pet only this time) started 'storing up' the attacks, but after it did we decided it was time to visit the Blaster Beetle again. Much to our joy it was re-spawned and almost as easy to kill as last time.
I've been told there are a few other 'uses' for some of these new bugs...