Dark lake

The dark lake is an enormous lake in Toriel's Underdark. Spanning from the City of blades to the north, to Neverlight in the south, the lake is considered the biggest subterranean body of water in Toriel.
The permafrost sea is said to be the source of the dark lake, with huge waterfalls draining it from the bottom.

Description

A endemic specy of algae live in the dark lake, a bioluminescent specy. The algae's bioluminescence is activated by movement. The lake's fishes and monsters provockes strokes of lights throughout the lake, and the movement of any boats can easily be traces for a few minutes as it leaves trails of light.

Features

Bioluminescence. Any creature moving within shed dim light within 10 ft.