Depending on how they are kitted, you might be able to drop a wraith knight with a cult, 18 shots that hit on 3s and reroll ones (2/3 + (1/6 * 2/3)) = 7/9 shots hit, wound on 6s reroll failed to wounds (1/6 + (5/6 * 1/6)) = 11/36 or just shy of one in three, with 14 hits that's 4 wounds a round, or 3 after the 5+
FnP. It's mildly awful from a points vs. points perspective, and would take two rounds, but with so many space marine armies out there you'll probably take the cult anyway.
This is my usual list these days:
http://www.dakkadakka.com/dakkaforum/posts/list/690185.page
That said, I've been avoiding the ghost ark for a while since I always played it that jink makes the units inside snap fire as well. The main reason I liked it was picking warriors back up, but as it was my only vehicle it drew copious amounts of anti-vehicle fire, so I've dropped it in my competitive lists and made my warrior squads bigger. As for the "Immortal lych deathstar", I have one because I have to have an answer to other death stars, but you guys have some weird ideas on how tough it is. It's got two resurrection orbs, but that could last one turn (my opponents phase and then my phase), so we are a tough deathstar for one turn out of five or six, otherwise, our deathstar has a low number of attacks, middling
AP (evenly split between
ap 2 and
ap 3), and decent
str (split between 5 and 7). Compared to most deathstars these days it's pretty lacking, and is dependent on support from the harvest to stand a chance against other death stars. The D-Lord is decent in challenges because of fear on
3d6 and void reaper, but only against units that aren't fearless.
As for passive awesomeness, if you gave us two wounds, it would be equivalent. However since it's
rng based people always way over estimate the effectiveness. A basic necron warrior is only slightly tougher than a marine, it takes 3
ap - wounds to get a
tac marine, and 4
ap - wounds to get a warrior, that's pretty far from the invincibility you guys seem to imagine us having. Warriors are also 4+, so there are lots more weapons that can bypass their armor save. Arguments about how
OP the harvest is completely ignore the reality that if you pop the spider they are not really that tough, requiring 36 wounds to down, or the equivalent of killing 9 warriors with
ap- weapons. However don't let math stop the onslaught of salt. I'm not saying necrons are weak, we are in a good place depending on the tournament rules, but we are hardly the invincible army you guys are claiming. Really the math isn't hard, and if you care enough to have an opinion, you should probably also care enough to have a correct opinion.