The boar, Varaha is regarded as the third avatara of Vishnu.
He is also regarded as the second purusha incarnation, when he is called, more properly, by the name Sukara (q.v.). He is described thus in scripture:
yatrodyatah kshiti-taloddharanaya bibhrat
kraudim tanum sakala-yajña-mayim anantah
antar-maharnava upagatam adi-daityam
tam damshtrayadrim iva vajra-dharo dadara
Lord Brahma said: When the unlimitedly powerful Lord assumed the form of
a boar as a pastime, just to lift the planet earth, which was drowned in the
great ocean of the universe called the Garbhodaka, the first demon [Hiranyaksha]
appeared, and the Lord pierced him with His tusk."
Bhag., Canto 2, Ch. 7, Text 1