Both the Death Star and Starkiller Base have the power to completely obliterate a celestial body in just a couple of minutes, completely devastating its population and erasing all traces of their existence. Similar weapons exist in Stellaris – though the effects of most of them are much more sophisticated than “planet go boom.” If you couldn’t care less about ethics and just want to establish dominance over a rival empire, these Colossus-mounted weapons are the way to go.
5. Neutron Sweeper
Destroying a perfectly good planet with something like the Planet Cracker is a waste of resources. Suppose all you want is to remove the planet’s geopolitical significance. In that case, a fantastic and straightforward alternative is the Neutron Sweep, which eliminates all pops on the planet in one fell swoop. Some people might tell you it’s also painless. But considering you’re irradiating the planet so hard it’ll take 10 years for the habitability penalty of -30% to go back down, I have my doubts. You won’t be able to use this planet-killer weapon if your empire is Pacifist or Spiritualist – but everyone else is A-OK.
4. Nanobot Diffuser
If you’re playing as a Driven Assimilator Machine Intelligence, you get access to the Nanobot Diffuser – an extraordinary planet neutralizer that’ll help you assimilate the planet. This weapon injects a plague of aggressive nanobots into the planet’s atmosphere. Like a virus, they’ll enter their hosts and modify them from the inside. Rather than destroying the celestial body, this colossal weapon turns all organics into cybernetics and hooks them up to your Gestalt consciousness. In addition, all incompatible Mechanical, Machine Unit, and Hive-Minded pops will be quickly disposed of. You can even use it on pre-FTL species!
3. Divine Enforcer
The Divine Enforcer is easily my favorite colossal weapon from a lore perspective. Firing this divine weapon on a planet won’t only dispose of Mechanical, Machine Unit, and Hive-Minded pops, but it’ll turn everyone into a devout Spiritualist believer. Moreover, the planet will have 999% Spiritualist ethics attraction, meaning they’ll never abandon the faith. To get this, you must be on the Psionic ascension path and unlock Telepathy, so I guess this weapon just streams televangelist content straight into the planet’s population’s brain. You can even use this weapon on your own worlds if you’re having trouble keeping the faith alive – but keep in mind that it’ll make everyone on it 20% less happy for a long while.
2. Deluge Machine
Probably the hardest part about playing as an Aquatic species is having to terraform every planet you wish to colonize – or hope that there’s a lot of H2O in your corner of the universe. Getting the Hydrocentric ascension perk makes this process a lot cheaper and easier – but you still have to struggle with red habitability before you finish setting that up. That is, unless you’re willing to use the Deluge Machine. This super-cool colossal weapon will turn any planet into Bikini Bottom and, in truly biblical fashion, drown all the non-aquatic pops on the surface, including machines. You can even target your own planets if you want to save on terraforming!
1. Star-Eater
The Star-Eater is slightly different from all the colossal weapons we just covered. Among other things, it’s not something you’d mount on a Colossus, but a unique ship you can only build after getting to the last level of the Become the Crisis ascension path. It also doesn’t target planets themselves but the stars they orbit around. Make no mistake, though – once you’re done with the star, all planets in the star system will be instantaneously destroyed. What it does is simple but terrifying: It turns the targeted star into a black hole, which proceeds to swallow everything around it but the Star-Eater itself. In addition to massive destruction, it’s a great way to get some Dark Matter! It’ll give you a new place to harvest it and a big bonus depending on galaxy size for each star you convert.