While one's (such as, a street seller or a stranger) back is turned to you, you walk away quickly, so when one's back is turned back around to return to you, they'll see that you're not there anymore.

WTF WHY YOU HERE I CANT UNDER STAND WHY THERE IS NTHING TO SHOW AND THERE IS NOTHING TO SEE SO WHY ATE YOU HERE??

Something alive but you can’t see

They are better seen in complete darkness, so you can see the static outline.

Part of the TF141, Ghost was second-in-command to Cpt. Mactavish aka Soap. Throughout MW2, he fought alongside Sgt. Gary ‘Roach’ Sanderson until the disavowment of TF141, when the betrayal of General Shepherd came into light.

Some believe him to be the literal reincarnation of Gaz from COD4, however this was never confirmed nor denied by Infinity Ward.