The glowing blue orb power-up in the Halo series.
When you pick it up, for a limited time, you become invisible.
When you fire, while in active camo mode, your invisbility will temporarily go away, only to come back after a few seconds of not shooting.
OMFG. That homo keeps getting the fucking active camo, and assasinating me !!!!!
*breaks controller in half*
by KoolKarlen July 21, 2009
Used to describe the effect perceived (or rather, not) when an African-American fellow is photographed or encountered in a dark environment.
"I never saw the thing coming, officer! It... it blended in with it's dark environment, then, then my purse! It was GONE! WHAT WAS IT?!"

"I'll tell you what it was, Ms. McFinney... One of them... African Americans. Over the years they've evolved some sort of... active camo!"
by Adam McDonald April 27, 2006