Chof Beis Shvat 5774
The Gemara (Sanhedrin 65b) relates that Rava once created a man by forming combining letters of Hashem's name, a feat revealed to him by studying Sefer Yetzirah. He sent the man to Rebbi Zeira, who attempted to carry a conversation with him, but received no reply as the man lacked the power of speech. Realizing what type of person this was, he proclaimed, "Return to your dust!" and the man ceased to exist.
Such miraculous beings have been created in more recent centuries as well. As an example, Reb Eliyahu, the Baal Shem of Chelm (not to be confused with the Baal Shem of Worms), was reputed to have created a man using Sefer Yetzirah. At one point, seeing that he was acting in an overly destructive manner, he removed the name of Hashem that was affixed to his forehead and he returned to the dust (see Responsa She'ilas Yaavetz, vol. 2 section 82).
A query can be posed: can such a man be counted as the tenth participant in a minyan? The need for ten men for a davar shebikedushah is derived from the verse, "And I will be sanctified amongst the men of Israel" (see Berachos 21b). Seemingly, such a person cannot be considered a "man of Israel," as he was not born from Jewish parents. On the other hand, however, "the creations of the righteous are considered as their offspring," and one can perhaps argue that they can thus be considered as Jews and be counted as part of a minyan. What is the Halachic status of such a person?