karmaapain posted...Don't know if it was a coincidence or what, but I've been having crossbones for a long time and I got a challenge reward (the one where you survive 10 rounds without turning on power) and when I got into the lobby I had a skull... Maybe it's how many rounds you go WITHOUT turning on the power. Has anyone tested this?
I ALWAYS turn on the power ASAP, so that is definitely not the answer.