Gunk is a liquid element. Like other liquids in Oxygen Not Included, it is affected by gravity, flows across open floor spaces and through open doors, and will stack into layers with other liquids based on density rather than mixing into a single tile. It cannot exist in amounts smaller than 10 g outside of pipes, and large accumulations can build pressure against surrounding tiles.
Because it is a liquid, Gunk follows the normal rules for phase changes and containment: it can freeze or evaporate if its temperature crosses the relevant threshold, it can damage liquid pipes if it changes phase while inside them, and it will be destroyed if exposed to space unless protected. Liquid tiles that are overfilled can also crack surrounding construction and eventually cause pressure damage, so any storage or processing setup for Gunk should account for the maximum mass a tile can hold.
Gunk also has a gameplay use in production. A recipe consumes 80 kg of Gunk to produce 1 unit of gear oil, and that output increases a Duplicant’s internal gear-oil amount by 80 kg when used. This makes Gunk a resource to keep in a stable liquid form if you intend to convert it rather than simply store it.
Gunk behaves like any other liquid for pumping, pipes, and liquid-airlock style setups.
It does not mix with other liquids in the same tile; instead, density determines layering over time.
If you store it in tanks or enclosed rooms, be mindful of pressure damage on weaker tiles.
In its liquid form, it is subject to the standard freezing and vaporization rules used by all liquids.
