Elvis Impersonators

Elvis impostors are a type of pedestrians in Grand Theft Auto 2 and GTA: San Andreas.

GTA 2
They appear in chains around the whole city, and aren't common. Killing them all in 5 seconds will grant you the Elvis Has Left the Building! bonus.

GTA San Andreas
They are very commonly spotted around Las Venturas, however they are just regular pedestrians and you'll get nothing for killing them, except some cash they drop.