Death Throes When the drake is reduced to 0 hp, it explodes in a cascade of magical energy. All creatures within 15 ft. of the drake must make a DC 15 Dexterity saving throw, taking 27 (5d10) force damage on a failure, or half as much on a success. Dragons and undead creatures are always considered vulnerable to this damage, even if they would otherwise be resistant or immune.   Deny Necromancy The drake always knows when a necromancy spell is being cast within 60 ft. of it, and can counter the spell (as the counterspell spell) as a reaction if it can see the spell being cast. Its spellcasting ability is considered to be Wisdom (+1) for this purpose.   Keen Smell The drake has advantage on all Perception checks that rely on smell.   Undead's Bane When the drake hits an undead cresture with a weapon attack, the attack deals an extra die of the weapon's damage type.