Vibrava (5e Creature)
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Small dragon, any alignment
Arena Trap. While the vibrava is on the ground, The ground in a 10-foot radius around it is difficult terrain. Each creature besides the vibrava that starts its turn in that area must succeed on a DC 13 Strength saving throw or have its speed reduced to 0 until the start of its next turn.
Ultrasound Vibration. If a creature starts its turn within 60 feet of the vibrava and is concentrating on a spell, the creature must succeed on a DC 13 Constitution saving throw or lose concentration.
Sand Tomb. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 12 (2d8 + 3) bludgeoning damage. If the target is a creature, it must succeed on a DC 13 Strength saving throw or be restrained for 1 minute. While restrained in this way, a creature takes 4 (1d8) bludgeoning damage at the start of each of its turns, and at the end of each of its turns, the target can repeat the saving throw, ending the effect on a success.
Bug Buzz (Recharge 5-6). The vibrava releases a sonic pulse. All creatures within 30 feet of it must make a DC 13 Constitution saving throw. On a failed save, the target takes 21 (6d6) thunder damage, and it is stunned until the end of its next turn. On a successful save, the target takes half as much damage and is not stunned.