ninja cookie 

When you throw a fart into a persons face.

She released the gas and ninja cookied her sister, causing her to gag.

ninja cookie by kaylacatcher97 November 17, 2016

Cookie Ninja 

Someone who is extremely proficient at stealing cookies without being spotted, regardless of how many people are in the vicinity.

Guy sees cookie.
Guy reaches for cookie.
Cookie disappears.
Guy cries.
Cookie Ninja has won.

Cookie Ninja by DLTZ April 28, 2013