The Cursed Candle can be found in woodland mansions, witch huts, pillagers outposts, and maybe igloos. The candle would not be craft able though. What it will do is increase the spawn rate of hostile mobs while the player is in a certain radius to it. The candle would be useless in the End dimension because it only increases hostile mob spawn rates, but in the nether it works. They also don’t effect mob spawners. These can be used to make the game harder in certain structures, find mobs easier, and could be used by map makers. Giving it a nether star will increase its range and giving it a diamond will decrease the range.