Originally Posted by Fat Ubiquitous
The reason for using Cofagrigus over spiritomb is nasty plot. The reason to use it over mismagius is MUCH better bulk in order to set up. I personally run TR nasty plot (with Shadow Ball and HP Fighting) and it is very effective.
If its anything like Trick Room Nasty Plot Slowking then its /very/ effective. Whilst it gets walled by Chansey due to lacking Psyshock it gets great Ghost / Fighting coverage and has much better bulk and defensive typing than Slowking. My only concern is that it'd lack power in comparison.