Liminal being

[2] Liminal personas are structurally and socially invisible, having left one set of classifications and not yet entered another.

[3] The social anthropologist Mary Douglas has highlighted the dangerous aspects of such liminal beings,[4] but they are also potentially beneficent.

Thus we often find presiding over a ritual's liminal stage a semi-human shaman figure, or a powerful mentor with animal aspects, such as a centaur.

[5] By extension, liminal beings of a mixed, hybrid nature appear regularly in myth, legend and fantasy.

One example is the sphinx: 'a liminal figure...straddling the divide between animal and human, and partaking of both'.