Scepter

the Chitauri Scepter' was used by Loki Laufeyson in the 2012 film The Avengers. It was given to him by Thanos. The staff utilized a blue gem powered by the Tesseract.

History
The scepter had a long golden handle and a black fitting which held a blue gem encircled with silver blades. It allowed its owner to open rifts through dimensions with the Tesseract as a gate key, fire powerfully destructive blue blasts of energy and bend the wills of others by controlling their hearts. The gem's influence controlled Loki's mind while he wielded it, turning his green eyes blue, which it also did to anyone whose chest he put the tip of the staff to, turning them into a puppet of his. This meant that while the Tesseract through the scepter had a grip on Loki's mind and mainly drove his actions, raising his hatred and desire to do harm higher than what they had been, he still retained his will.

Loki used the scepter to brainwash Hawkeye, Dr. Selvig and numerous S.H.I.E.L.D. agents into his followers, turning their eyes crystal blue like his. He could transform it at will from its long, fully-extended appearance to its smaller but equally deadly form the same way he transformed his own appearance with and without his full body armor and cape. He also disguised it as a walking cane when disguising himself amongst humans. The staff also functioned as a spear, being able to violently impale and slash enemies, besting most in combat with ease. It was even strong enough to match Thor's mighty hammer Mjølnir in close-quarters combat.