Deathstalker
The Deathstalker is a type of Eldar Super-heavy grav-tank that have never seen the days on tabletop since the ye olde age of Epic. From what we can tell the Deathstalker is armed with a heavier version of the Prism Cannon meaning that it is essentially the Fire Prism on steroids and seeing how OP the Fire Prism was on both tabletop and Dawn of War Emperah help us if Forge World decides to have an update on this beast.
According to age old fluff, multiple Deathstalkers can combine their fire into a chain to produce a much more powerful blast, meaning that this thing has the potential to turn your Titan legions into slag of molten metal