"Like many Canoptek constructs, these repair units are created by the Crypteks to keep the tomb worlds and their armies in tip-top shape – whether they’re taking a well-deserved rest or scourging the universe of any upstart civilisations who’ve moved in over the millennia. On the battlefield, you’ll find your Canoptek Reanimators the perfect accompaniment to your valuable troops, helping you nail those all-important Reanimation Protocol rolls."
- – GW Description.
Martian Tripod Harvester Canoptek Reanimator is a giant canoptek construct that first made its appearance in Warhammer 40,000 9th edition. Yes, yes, we know, this is like the third/second War of the Worlds ripoff after the Spindle Drones from Blackstone Fortress and its Doomstalker cousin. What? you think GeeDubs are not acting like corporate hypocrites even with their recent name change of all their factions and units to acquire copyright material? Don't make us laugh.
The Canoptek Reanimator is basically a giant version of the Canoptek Spyder. They could repair damaged and destroyed Necron constructs with their reanimation beams from their Atomiser Beam Lance, just on a much larger scale. As such, expect them to only be around when a massive shit hits the fan, you ain't gonna send in a superheavy ambulance truck to what counts as a minor paper cut, would you?
Also, these guys aren't some harmless glorified medics. This is 40k after all, so expect the nurse to just be able to heal a wound as it is, skewering you like a kebab. On the battlefield, the Reanimator could use its long legs as giant spears to go all Cannibal Holocaust on its enemies. At range, it could use its very reanimation beams and turn it into a literal War in the Worlds' style disintegration beam (Seriously GW, please be more subtle). So essentially, these things are like Star Trek Phasers, if only the Phasers could heal people too (Wow! One of the few times that something in Star Trek is actually more Grimdark than its 40k counterparts).
On tabletop, what has been said in the fluff can be accurately applied to the crunch. Their Atomiser Beam Lance has this special rule called Nano-Scarab Reanimation Beam: which, in your Command Phase, you can select one friendly Dynasty unit within 9" of this model. If you do, until the start of your next Command Phase, while that unit is within 9" of this model, add 1 to Reanimation Protocols rolls made for models in that unit. Also, were we the only ones who immediately felt the urge to yell 'cheese!' upon hearing of this thing?
...too bad the 9th edition rules for Reanimation Protocols are out now, and this thing has been revealed to be an overpriced heap of scrap metal that nobody in their right mind will ever even consider to field. It peeks out of most cover, the range of its gun is pathetic, it doesn't really want to be in melee, it can't hide behind troops like a character and at T5, lasguns can pling it off the table if they really want to. All in all, it's a Cryptek except worse at everything a Cryptek does. But hey, if you glue a laser pointer on top it can count as a Doomstalker, probably?