A homunculus with the ability to shape shift at will and take any form "IT" desires.
The 4th homunculus created by Father in the manga/2009 anime. Genderless despite being often refered to as a "He".
SPOILER FOR 2003 series:
Is the 1st homunculus, created by Hohenheim who attempted to resurrect his and Dante's son, who died of mercury poison. Developed a loathing for his "fahter" when he abandoned him and eventually settled with a new family (Ed and Al).