Craag's Hellion Hunter (5e Equipment)
From D&D Wiki
weapon (javelin), rare
This blessed magic weapon's special abilities only activate upon being thrown at an undead, fiendish, or cursed creatures. When targeting one of these creature types, you gain a +3 to that attack roll. On a successful hit the weapon deals an additional 5d4 radiant damage (flaring with red, blue, green, yellow, and black radiance for each 1d4). On a critical hit, the target is pushed 10 feet in addition to the extra damage.