Abihu

ABIHU (a-bī'hū, Heb. ’ăvîhû, the father is he). Second son of Aaron (Exod.6.23). With Aaron, Nadab his brother, and the seventy elders he went with Moses up Mount Sinai for a limited distance (Exod.24.1). It was his privilege to see the God of Israel (Exod.24.9-Exod.24.11), but subsequently he died under divine judgment because he offered “unauthorized fire before the Lord” (Num.10.1).

International Standard Bible Encyclopedia (1915)

Second son of Aaron, the high priest (Ex 6:23). With his older brother Nadab he "died before Yahweh," when the two "offered strange fire" (Le 10:1,2).

It may be inferred from the emphatic prohibition of wine or strong drink, laid upon the priests immediately after this tragedy, that the two brothers were going to their priestly functions in an intoxicated condition (Le 10:8-11). Their death is mentioned three times in subsequent records (Nu 3:4; 26:61; 1Ch 24:2).