Night Raids

The night is no longer the safe part of the day. After dark, enemies at polluted nests gather and set out for whatever is polluting, on top of the game's usual attacks.

What it does

Raids after dark: while it's night on a surface, there's a 50% chance of a raid every 45 seconds, with at least 90 seconds between raids. Nauvis's night is only about 2 minutes long, so expect one or two a night.
Darker means bigger: each polluted nest joins a raid with a chance equal to how dark it is, so a raid at deep night draws from more nests than one at dusk.
Your pollution decides who comes: a nest only takes part if pollution reaches it, even a trace at the edge of your cloud. Clean nests stay home, and nothing raids by day.
Raid leaders: each group of 5 or more gets a leader, one extra unit a size above most of its pack. It's red, larger and has half as much health again. A pack of behemoths gets a behemoth leader.
Any planet with nests: each surface has its own night. In vanilla that means Nauvis and Gleba, and Gleba's stompers join in too.

Settings

Show time until night or day (per player, on by default): a small display counts down to nightfall or daybreak on the surface you're on, top left or top right. Night starts when raids can start.

Attack only in night raids (startup setting, off by default): the big one. Nests stop sending the game's normal attacks and store the pollution they absorb. Each raid spends what its nests have stored on new attackers, until a nest has 100 enemies around it, and at most 500 new ones per raid on a planet, so everything your pollution would have sent during the day arrives together after dark, and a dirtier base gets bigger raids. Raids also wait out the daylight.

Decide on this one before you settle into a game. Turning it off or removing the mod later makes nests spend everything they ever stored, in large waves that can go on for a long time.

The rest are map settings, so you can change them during a game.

Raid leaders (on by default): turn this off for raids without leaders.

Extra raiders (0 to 200%, default 10%): for a real challenge. Each raid group gains this percentage more of its most common enemy, on top of its leader. At 10%, 10 small biters become 11; at 200%, they become 30. Set it to 0 to add none. A nest with 200 enemies around it adds no more, and a raid adds at most 500 new enemies on a planet, so raiders that can't reach anything don't pile up.

Warn when a raid starts (on by default): prints a message in the console when a raid sets out, naming the planet. Turn it off if you'd rather be surprised.

Show where a raid starts (on by default): adds pings of the places the raid set out from to the end of that message, up to 5. Nests close together count as one place.

Attacks move only at night (off by default, and always on while "Attack only in night raids" is on): enemy groups on their way to attack stop and wait while it's light on their surface, then carry on after dark. Those already fighting keep fighting.

Enemies still build up during the day, so night attacks can get very large.

Good to know

The raiders are ordinary enemies under the game's own AI. Nothing about how they fight is changed.
A raid takes every enemy unit close to the middle of a nest's chunk, which may include units that were already in a group.
With the night-only setting on, an attack that another mod ordered by script is cancelled if it's stopped, and it doesn't resume. Leave the setting off if a mod you use relies on those.
Works with or without Space Age.
Can't run alongside Nightfall or Nightfall (Continued), which do the same job.

Thanks

The idea and the balance come from Nightfall by Yehn, and its continuation Nightfall (Continued) by Ramasees, which run on older versions of Factorio. This is a new mod with its own code.