I'm baffled by both the fighting in these comments and the overall vehemence. If you want to put a cool cursed item in your game, just drop it when the players are still too low level to have remove curse...or make it subtle enough that they don't initially realize it's cursed.

EDIT: NVM I just realized you're all trying to ape the critical roll thing and didn't plan for getting player buy-in or homebrew