Infinity Vine

An infinity vine is one huge plant of countless thin, tangled, bright green stems with no leaves. Tiny blue flowers, half an inch across, pull water and food from the air. Given breathable air and any light in the void between worlds, it grows as if from nothing.

Crews scrape it from infested hulls and toss it overboard, and dormant scraps drift until one touches the air envelope of a starship or a small body under 100 miles wide. It then spreads 10 cubic feet per round, up to 10 feet deep over every lit outer surface (never into darkness). A fully covered ship weighs four times its normal tonnage, ruining its starhelm flight.

It harms no one directly but engulfs slow or helpless beings. Forcing through by hand lets a creature move its movement rate in feet each turn, with the vine regrowing behind it; claws or a dagger double that, and a short sword or bigger blade triples it.

Flame destroys it on contact, though burning a ship clean is impractical. Darkness or submersion halts growth. Fire, acid and lightning spells clear their area (it regrows from elsewhere); cold spells stop growth there for a round per point of damage; darkness, charm plant and hold plant stop it in their area; plant growth raises growth to 100 cubic feet per round, still 10 feet deep at most; and magic missile damage refills almost instantly. Haste, slow, entangle, spike growth, plant door, transport via plants, anti-plant shell and enlarge/reduce work normally, a resized vine regrowing or shrinking to its old volume. It is immune to plant diseases and all poisons (even cloudkill), polymorph, energy drain and death magic.

It will not grow on bodies over 100 miles across. The flame-sea withers it brown and brittle but only dormant; returned to light and air, it regrows in one turn. Crews clear ships by entering the flame-sea and scraping, hiding in a planet's shadow, or landing on a large world, where after an hour it shrinks away at 10 cubic feet per round.

It consumes air-breathers' waste gases, releases oxygen, and doubles the air envelope of what it covers. It is edible but bland, so vine-choked asteroids can shelter castaways and exiles.