Other instances of being "Mars'd" include finishing any adventure with a d20 average below 4.0. This is also referred to as "being Mars'd".
Apparently, if you have him on your team and he "buffs" you, you receive -1 on all rolls for the next three encounters.
"Man, I can't stop getting Mars'd!"
"Damn you Mars!"
Captain Kirk: "MARS! I mean KHAN!"