geki ni （げきに）

The friend who taught me this phrase said it meant "Sugee niteiru ( すげぇーにている )."  I supposed some English equivalents would be "(someone's) double," "lookalike," doppleganger.

He taught it to me a few years ago, maybe four or five.  At the time, it seemed like a newer word; I guessed that it might have been a slang term created and used by younger people, as a lot of my older students and acquaintances had never heard it and didn't understand me when I tried to use it.  It didn't seem to offend anyone, as slang sometimes does. . .In fact, it brought some to laughter.  I never knew why.