This is a “dance special” where 4Minute (mostly Hyun-a) dances to Bad Girl (Usher) and Deja vu (Beyonce) as well as performs a “dance version” of Muzik.
Credit: source video yoobin.skyrock
Sensitive readers should perhaps skip this video since Hyun-a’s dancing is a bit on the “stripper” end of the spectrum 
2009-11-30 (Mon) 05:36
thanks ^_^