Best scifi tank?

[The Enclave]

The Mark XXXIII Bolo tanks and the larger of the nonstandardized Bolo tanks that came afterwards take first place easily in my opinion.

Now to back up my statement; While I find the idea of a single tank being able to adequately defend an entire planet to be somewhat incredulous, it's hard to argue against a tank that can take on Starships in low to mid level orbit and win. Now I am not sure how Boloverse starships compare to heavy weights like Star Wars or Warhammer 40,000, but I must say that I am quite impressed by this feat.

Now of course I realize that other people have already said this and have probably provided better arguments, but I'm just doing what I can with my fairly limited knowledge of the subject matter.

[Coyote]

Would such a "tank" really classify as a tank? Or some sort of land-Leviathan/mobile planetary defense base?

I mean, it's not like you have to bother with learning tankers' fieldcraft, like traveling in formation, maintaining convoy distance, maintaining overlapping fields of fire, conducting fire and maneuver, mobile overwatch, etc...

[Luzifer's right hand]

*snipped stuff about Perry Rhodan Shifts posted by myself and Batman*

This.

The original Shifts are flying tanks which are built with the motto "Jack of all trades, master of none". A armoured vehicle which can drive on tracks, is an anti-grav vehicle, can operate on- and under-water(and other fluids, like on gas giants) fly in an atmosphere and space(but the first versions could not reach space on their own).
The original authors were rather fond of English, thus the name. A Shift can "shift" from one environment to another without problems.
More advanced Shifts can also operate a short-ranged space-ships without FTL drive and some versions have no tracks.

Originally there was only one class of Shift but later more specialized versions showed up.
For example an armoured transport Shift of the LFT(a Terra based government in the setting) which is also sold as a civilian version without a gun turret. This a is a track-less Shift. There are also scout, stealth and pure combat shifts.

Specifications:
Dimensions: length: 12.0 m height: 2.8 m (without extended turret) width: 6.5 m
Mass: 38.500 kg + 15.000 kg load capacity
Crew: 2 + up to 14 soldiers
Energy Supply: 2 accumulators 5.6 GW for 720 h, emergency hyperspace-tap which can charge the accumulators once(normally they are charged by a mother-ship or base), a matter->energy conversion reactor 2.5 GW for 720 h
Drive: a gravity based drive with a max. acceleration of 250 km/s²(limited to 0.4 c ), max in-atmosphere speeds of Shifts with the same technology is in the 6000-9800 km/h range(the exact number for this Shift type is not known)

Armament:
Offensive:
1 transform-cannon with a maximum yielf of 5 MT. Teleports warheads inside their targets(unless shields which block such attacks are in the way), ignores matter and the warheads can emerge inside solid objects.
2 "MVH"("M"ulti-"V"ariable-"H"yperweaponsystem)-emitters each with 780 MW energy supply.
This weapon system has different settings a bit like phasers.
Paralysis-beam: A non-lethal weapon system, does no work trough most shield types used in the setting.
Desintegrator: A lightspeed weapon system which disintegrates matter, does not work against high-energy- and paratron-shields. Side effects involve dust which can be deadly to lifeforms.
Impulse-cannon, near lightspeed technoabble particle weapons, a directed fusion reaction which is buffed with hyper-space technobabble. Does not work against paratron-level shielding. However yields are only know from ship mounted weapons(500 GT per shot for example) and the small arms version(for example 3 kg TNT equivalent per shot).
Defensive: A three layer high-energy- and paratron-shield combination, they work by shunting energy in hyperspace, a cloaking device(a standard technology in the setting, bends light around the vehicle), a "virtual imager": absorbs emissions(electromagnetic and gravimetric) and transmits them to another point as a decoy.

A group of different Shifts

[SylasGaunt]

The Mark XXXIII Bolo tanks and the larger of the nonstandardized Bolo tanks that came afterwards take first place easily in my opinion.

Now to back up my statement; While I find the idea of a single tank being able to adequately defend an entire planet to be somewhat incredulous, it's hard to argue against a tank that can take on Starships in low to mid level orbit and win. Now I am not sure how Boloverse starships compare to heavy weights like Star Wars or Warhammer 40,000, but I must say that I am quite impressed by this feat.

They don't compare well. The reason Bolos are such stupendously destructive ground combat platforms is because their universe doesn't have the massive gap between ground force firepower and starship firepower that others have. Bolos usually mount weapons that are the equivalent of the time period's battleship armament. It's like having a tank packing a 16 inch gun for its AT armament.

Now they can also defend much larger areas than their size would suggest due to a mix of speed, indirect fire (both ballistic and missile types, including some that IIRC can go into hunter-killer mode and attack things on the other side of the planet) and with some later mark Bolos their drone tanks. Usually though the only time we see 'lone bolo protecting a whole planet' is when there's a dinky little colony where you can stick the bolo near everything important. Bigger, more important worlds are going to need more bolos to protect everything.