If you aren't familiar with this lonely little fella, allow me to give you a little background first. According to the fluff, it drained the life from an Eldar craftworld single handed leaving an empty shell behind. No small feat. The picture in the codex has it looking like a Zoanthrope on steroids with a long spine-tail. In game terms, it is like a Zoanthrope but with better WS, IN, AT, ST and WD. It's real potential and pucker factor comes from it's ability to kill models at the beginning of EVERY shooting phase. Every enemy unit w/in 6" takes a Ld check on 3d6. How ever much you fail it by, you take wounds (no armor saves) and Doom gets those wounds. This little guy can have up to 10 wounds and it's strength is equal to the number of wounds it has. After draining, it can fire a large blast (AP1) at it's current strength value. The raging debate currently, is if his power affects units in vehicles or not. The prelim FAQ (GW hasn't released an official one yet) is that is can but they get a cover save. Not too shabby.
GW didn't release a model, so I had to put one together. I used 2 genestealer bodies, mawloc/trygon/carnifex parts and some putty (for the brain). Not real complicated, but effective. You get the idea. I intend to use it in Bolscon to drop (via spore pod) in close proximity to as many enemy units as possible and cause as much disruption as possible.