1. It refers to the questionable or silly coaching decisions made by Mike Shanahan that negatively impact fantasy football owners who start NFL players that are coached by Mike.
2. It can additionally be used to describe the questionable or silly coaching decisions that negatively impact the NFL team in which Mike Shanahan coaches.
This is Shanahanigans!
(This actually occurred in the 2010 Week 8 Redskins v Lions game on 10/31/2010)