Portals
Portals connect separate underworlds.
A portal is a fixed connection between two underworlds. It is neither an ordinary shaft nor an exit to the surface: anyone who reaches and crosses the opening enters another burrow. The connection belongs to the generated world and leads to the same destination each time.
Another burrow
Unknown chambers, stores and inhabitants may lie on the other side. Crossing does not change a slime's species; the same underground rules still apply to it there. A portal provides a short passage between places, but neither protection nor ownership. What can be reached from the arrival point depends on the tunnels actually dug on either side.
Discovery by approach
A portal's mere existence in the generated underworld is not yet knowledge held by a colony. Only when one of its members comes close enough is the connection recorded in the Bestiarium. A free camera or an already revealed surface biome does not replace that encounter. Nor does it instantly reveal everything on the far side.
Beyond the opening, the passage smelled different, and unfamiliar spoil lay against the walls. Nothing on the surface hinted at this neighbour.
