Cretaceous Collector

I wouldn't be surprised to see the achievement strategy for this involving 3 tanks. 1 less DPS is fine in any overgeared group, and the third tank could just pick up the adds incrimentally and hold them.

While no means necessarily, I'm sure that it would greatly simplify the lives of the current tanks (ie, proper swaps, proper prevention of the DPS accidentally AoEing the dinomancers, etc)

You do not have to activate every gate to get this achievement. My guild burnt Horridon down at the second gate and got it.

Dinomancers are part of the adds spawning during Horridon phase 1. They come one by one for each troll tribe. This means that for this achievement, you have to be able to survive with 4 dinomancers.

During phase 1, for each tribe 3 trash waves spawn each containing wastewalkers. After you kill 3 wastewalkers, a dinomancer spawns. This dinomancers can heal Horridon by channeling a spell healing 1% per 3 sec. This spell is interuptable and should be interrupted. After they are down to 50% they transform into a dinosaur and are not able to channel this healing spell anymore. However, they do more physical damage and drop an orb of control. Clicking this will lock the current door and prevents trash from spawning through this door.

So to achieve this you will eat the damage through out the fight. Most likely you want to dps down the dinomancers to 50%, so you dont have to care about interrupts.

This information is based on ptr and raid testing and can be changed in the future. I will try to keep this post updated.