History and specifics
Polymax VIII was a class M, Earth-like Federation planet, the homeworld of a Human or humanoid civilization with three billion inhabitants who built cities and broadcast regular subspace signals. It was 12.5 hours away from Tasus at maximum warp.
In 2270, the starship USS Enterprise was en route to Polymax VIII for routine resupply when contact was lost. By the time the ship entered orbit, Polymax VIII had been flooded, with its oceans toxic and its atmosphere too humid for breathing, which resulted in the deaths of all intelligent life. The planet's magnetic fields had also been disrupted, a catastrophe caused by a madman, Ulum. (TOS - New Visions comic: "What Pain It Is to Drown")