Was in a clan that mostly played Halo. Clan tags were "SX" followed by your clan number (I was the 21st member, so I was SX21), gamertags were "x(insert thing here)x(clan number)". I was really good with plasma weapons and grenades and was starting chemistry classes at the time, so I chose plasma because of how people both know it exists and know nothing about it at the same time. Long story short, the clan dissolved after Reach with lots changing their name to "Light" and then a name (so I would have been "Light Plasma") but someone had already used my name. Being the last SX clan member with his old GT, I just kept using it.