This build uses Dark Convergence (set) along with Occult Overload (slotted CP) to suck trash mobs together and make them explode. If you thought Dark Convergence was fun (or miserable) in PVP, wait until you try it in PVE.

You can easily customize this to any class, just swap out the ground AOEs/DOTs. Use a monster set and jewelry/weapon set that either casts an AOE or makes your AOEs more powerful. (Nerien'eth and Kinras are used here.)

With enough trash mobs, you can get over 100k in a single explosion in overland content, casting only DOTs, never doing direct damage or touching your spammable. Great for random normal dungeons and grinding.