Plug Slug

Plug Slug is a critter that generates electrical power by plugging itself into wiring while it sleeps. They scale walls and walk along ceilings, and during the night they hang down from a ceiling tile to create a two-tile tall socket (the lower tile is the active socket) from which power can be drawn. Plug Slugs prefer to plug into exposed conductive wires and cannot share a sleep tile; their socket cannot overlap buildings such as Storage Bins. They are found naturally on the Swampy Asteroid in the Spaced Out DLC (at least five mature individuals spawn there) and additional wild specimens may appear in Swampy pockets on other asteroids. Plug Slugs can be printed or transported for use elsewhere, making them a convenient remote power source.

A tame Plug Slug has a base night-time output of 1600 W when well fed, with reduced outputs at lower calorie thresholds: 1200 W below 5000 kcal, 800 W below 3000 kcal, and 40 W when starving. Wild Plug Slugs produce exactly one quarter of tame output at each tier (so up to 400 W when well fed), but starving slugs of either wild or tame state output 40 W. Night lasts 75 seconds in the game’s 600-second cycle, so a fully fed tame slug delivers up to 120 kJ per night (1600 W × 75 s) and a wild slug up to 30 kJ per night; averaged over the full cycle this is roughly 200 W for a well-fed tame slug and 50 W for a wild slug. Power output is determined when a slug becomes drowsy and is independent of happiness and other statuses.

Plug Slugs eat unrefined metal ores and refined metals and excrete hydrogen when consuming metal; this gives an additional hydrogen byproduct (roughly 3 kg/day per well-fed slug) that can be used to run hydrogen generators. Cracking a Plug Slug egg yields 1000 g Raw Egg and 100 g Egg Shell; a slug’s corpse drops 3200 kcal (2 kg) of Meat.

There are three morphs of the Slug family that share the same diet but have different utility. The Plug Slug is the power-producing morph. Spending time in unbreathable gases increases the chance a Plug Slug lays a Smog Slug egg; spending time in liquids increases the chance of a Sponge Slug egg. Smog Slugs inhale non-breathable gases during the day and expel them into pipes at night, functioning as a mobile gas filter. Sponge Slugs inhale liquids during the day and expel them into liquid pipes at night, acting as mobile liquid pumps. These alternate morphs can be useful as critter-based replacements for pumps and filtered gas pumps but are more complex to exploit in practice.

Practical notes and strategies:

• Taming and feeding: tame Plug Slugs produce substantially more power than wild ones, but they consume metals that are otherwise valuable. Their food requirement and hydrogen output are affected by happiness; glum tame slugs have reduced food consumption and hydrogen output but retain full direct power output per night.
• Semi-starvation exploit: power output is decided when the slug becomes drowsy. Briefly feeding a starving slug right before it becomes drowsy lets it produce the higher-power tier for that night while minimizing total food consumed. Feeding while drowsy requires very little food to reach the needed calorie threshold and yields dramatically better energy-per-food ratios than continuous feeding.
• Placement: slugs must sleep on ceilings and prefer exposed wires; ensure their socket tile is clear of buildings and wiring access is arranged at the correct height (two tiles below the ceiling). Because only one slug can sleep per tile, plan ceiling space accordingly.
• Complementary systems: pair Plug Slugs with batteries to smooth their night-only output and with pumps to harvest hydrogen byproduct. Four wild slugs or a single well-fed tame slug produce power comparable to a Manual Generator for short bursts, but sustained utility favors tame slugs buffered by storage.
• Use cases: Plug Slugs are convenient for remote or early outposts where wiring up conventional generators is impractical, and they do not disable the Super Sustainable achievement. They are less attractive as a long-term primary power source due to metal consumption, but excel when wild-slug power is freely available or when exploiting the semi-starvation feeding strategy. Smog and Sponge morphs provide non-electrical niche uses such as passive gas filtering and liquid transfer without mechanical pumps.