Ancient Rime

Cold light from the ancient frozen star Verglasz waxes over the ground on a 10' square centered on a point within range, turning it into difficult terrain by flash-freezing it with a thin, nearly invisible layer of black ice and hoarfrost.

When the ice appears, each creature standing in its area must succeed on a Dexterity saving throw or fall prone and suffer 1 cold damage.  A creature that enters the area or ends its turn there must also succeed on a Dexterity saving throw or fall prone and suffer 1 cold damage.

Magical heat or flame effects in the area that deal at least 5 fire damage, or non-magical sources that deal at least 10 fire damage, end the spell immediately.