Nova Cannon
The Nova Cannon is a weapon in Battlefleet Gothic, no THE weapon in Battlefleet Gothic, noteworthy for the fact that it creates small blast templates. This may not sound all that impressive until you remember that in Battlefleet Gothic the centre of the base represents a spaceship the size of a hive city. So on this scale, a nova cannons blast is destroying an area of space the size of a large continent. In one shot. A fuckmothering continent. Just think about that. That's the sort of Grade A fucking insane "Humanity Fuck Yeah" ridiculously violent scale we're dealing with in Battlefleet Gothic. This is why it is awesome. It allows something like this to exist.
What this mad bastard actually is varies depending on who you ask. Is it a railgun? A vortex missile? Every damn bit of explosive on a forge world shoved in one container? No-one is entirely sure, but one thing is certain. If an enemy ship has a Nova Cannon you stay the hell away from that magnificent beast unless you wish to suffer sudden massive existence failure. I'm not even joking. Just stay the fuck away.
And then there's the Planet Killer. Jesus. Fucking Christ.