evil twin

noun2

1. •
   A duplicate or counterpart that acts in a contrary, nefarious, or insidious manner.

   • As a ploy to discredit the reformist politician, the opposing party had hired a lookalike to act as his evil twin and be seen in a variety of compromising situations.
2. •
   A rogue wireless access point installed near a legitimate one for purposes of eavesdropping or phishing.