We need to be careful. Current fads involving angels, ecstatic worship and necromancy could push us off the edge of spiritual sanity.
No one fully understands what Nadab and Abihu did to prompt God to strike them dead in the sanctuary of Israel. The Bible says they loaded their firepans with incense, ignited the substance and "offered strange fire before the Lord, which He had not commanded them" (Lev. 10:1, NASB). As a result of their careless and irreverent behavior, fire came from God's presence and consumed them.
Zap. In an instant they were ashes.