Odd-looking but Human-like robots
In 2011, a civilization made first contact with a far more advanced alien species. As Samuel predicted in his answer, the contact took the form of a robot meant to mimick the denizens of the less advanced species.
The robot in question was RoboBee, built by Tim Landgraf et al in a bid to learn more about the bee's language of dancing (2). Communication was one-way and only partly succesfull, yet a first-contact for the bees, in terms of communication. The experiment lends credence to the argument bowlturner makes under the above question, that aliens would mimick us to make themselves understood. In the case of bees, a bee-like body was essential to get communication across at all. Note also that in the bee-robot encounter, the mysterious builders of the robot could not have walked among the bees in their true form.
I am RoboBee, ambassador from the human race to lesser developed species.
I have made contact with the natives. They are receptive to my messages, but appear to be controlled by some kind of hive mind.