Zweilous (5e Creature)
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Medium dragon, any alignment
Hustle. Once per turn, before the zweilous makes a melee attack, it can choose to take a -5 penalty to the attack roll. If the attack hits, it add +10 to the attack's damage.
Two Heads. The zweilous has advantage on saving throws against being blinded, deafened, stunned, or knocked unconscious.
Wakeful. When one of the zweilous's heads is asleep, its other head is awake.
Multiattack. The zweilous makes two bite attacks.
Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) piercing damage plus 3 (1d6) necrotic damage.