"Ak! Urgh! Oh GODS I hate these guys!"
- Me on encountering Salt Mephits in DDO
There are many, many types of Mephits (and Mephlings if you are a 3.0 / 3.5 type player), and as a rule they are all horrible. In DDO, you will battle countless Mephits at almost every level of play. You will grow to hate them.
However, out of all the Mephits I encountered in that game, none had me roaring in fury more than the horrible Salt Mephit. Admittedly, in that game they could blind you, which always sucked. However, their D&D stats hardly made them any less monstrous, especially given their low CR (in both earlier, and as it happens, this edition).
Anyway, it's time to make your players feel the pain. Enjoy.