A statement concerning Diplomatic Relations from Edge of Eternities.

Incorrect:

Target creature gets +1/+0 and gains vigilance until end of turn. It deals damage equal to its power to target creature opponent controls.

Correct:

Target creature you control gets +1/+0 and gains vigilance until end of turn. It deals damage equal to its power to target creature opponent controls.

Definitely seems like something that could come up in Limited