Frost sword

The Frost Sword or Ice Sword is variety of enchanted blade which is imbued with the magical properties of ice, which allows it to cut with searing coldness. Variants of this weapon appear in the SNES Port of Ultima VII and in Ultima IX.

Description
Frost swords existed in the last days of the Avatar, and proved deadly weapons against many of the ravaging daemons and hellhounds which stalked the corrupted realm of Britannia in those days. In addition to dealing bitter damage to their victims (40-60 damage per stike), such blades had a substantial chance (40%) of causing those it struck to freeze solidly to the ground upon which they stood, rendering them helpless in the face of a potential killing blow.

Ultima VII (SNES)''
In the SNES Port of Ultima VII, an ice sword appears, which is ineffective against ice-aligned or elementally-invulnerable creatures, which includes: cyclopes, headless, stone harpies and trolls. Unlike the sword in Ultima IX, it does not cause opponents to freeze

Ultima VII (SNES)
Ice swords may be found at the following locations in the SNES Port of Ultima VII:
 * Serpent's Hold (Sold by Ward for 500gp)

Ultima IX
Frost swords may be found at the following locations in Ultima IX:
 * Buccaneer's Den (Sold by Warrick for 2420gp)
 * Iceberg to the north of the Britannian mainland