That would get very annoying in pvp where somebody could just freeze you and get a free hit or a free kill!
Probably it would be like you freeze an enemy on death so if you are on an ice planet, you could have ice statues everywhere
Also, the ice could effect the terrain as well. So, it would add to the strategy, since if you are not careful the problems with a slippery floor and ice blocks in the ground backfires in the weapon user. Maybe some sort of defense against the weapon, too?
I can see how this would get annoying in pvp terms, unless it would have a different effect on player enemies. Instead of freezing player enemies in place like it would do to normal enemies, it would have a chance to cause a sort of temporary slow status effect, but it would still freeze on death so there could still be an ice statue.
A freeze ray? I like it! I can't get Dr. Horribles sing-along-blog outta my mind. I think a freeze ray would suit the sci fi theme very well. Also, it would have non-combat applications as well