I was born at a surprisingly young age to parents who had been carefully selected for genetic compatibility. Alas, the ultracomputator that performed the selection was then found to have been in error, due to a small but statistically-significant deviation in its n-space trajectorizing software. But the damage had been done. There I was.
Attempts to rectify the mistake failed, including a desperate sub-quasar quantum-spin correction. The quantum spin was, in fact, synchronized, but again, alas… apparently it was not the problem.
So, realizing that I was indeed going to remain as I was, my parental units proceeded to do the only thing practical; namely, offloading me whenever possible to THEIR parental units. While this, too, did not have the desired effect, it did afford me an opportunity to observe multiple generations of humankind, so that I became better equipped to appear as one of them.
Except for an occasional pan-dimensional lapse, none of which could be sensed or experienced by the beings of Earth, I have continued existence in human-form, extruding sonic tendrils into human earspace, in the hopes that maybe, just maybe, another of my kind may recognize my call and join me.