The yakkha of Āḷavī. The Buddha once stayed at his dweling, at which the yakkha became angry and threatened the Buddha. He was tamed by the Buddha and asked a series of questions Snp.p.31–33 SN.i.213ff.
Āḷavaka’s name appears in the Āṭānāṭīya Sutta, among the Yakkhas to whom followers of the Buddha should appeal for protection in time of need. DN.iii.205