Flyby. The lightning wyvern does not provoke opportunity attacks when it flies out of an enemy's reach.

Multiattack. The wyvern makes two attacks: one with its bite and one with its tail. While flying, it can use its claws in place of one other attack.

Bite. Melee Weapon Attack: +6 to hit, reach 10 ft., one creature. Hit: 9 (2d6+1) piercing damage.

Talons. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d8+2) slashing damage.

Tail. Melee Weapon Attack: +7 to hit, reach 15 ft., one target. Hit: 13 (2d8+2) bludgeoning damage and 2 piercing damage.

Sparking Fireball. RangedWeapon Attack: +7 to hit, range 35/80 ft., 1 target. Hit: 7 (1d8+1) fire damage and 8 (1d8+2) lightning damage.

Chain Lightning. Ranged Weapon Attack: +8 to hit, reach 20 ft., one target. Hit:  21 (4d8) lightning damage, and lightning jumps to one creature of the ball lightning's choice within 30 feet of the target. That second target must succeed on a DC 14 Dexterity saving throw or take 12 (2d8) lightning damage. Then, if that creature fails its save, the ball lightning chooses another creature within 30 feet of the second creature that has not been targeted by this attack yet. The new target must make a DC 15 Dexterity saving throw or take 12 (2d8) lightning damage. If that creature fails its save, repeat the process of choosing new targets to make saves until either  a creature succeeds or all viable targets have been targeted.