You conjure a wyvern made of lightning that obeys you. The wyvern uses the same stat block as a normal one with these changes: 

The wyvern is a chaotic neutral elemental.

The wyvern's bite and sting attacks deal an extra 5(1d10) lightning damage.

The wyvern has the additional trait: Lightning Breath (recharge 5-6). The wyvern exhales lightning in a 60- foot line the line is 5 feet wide. Each creature in that line must make a DC 16 Dexterity saving throw taking 55 (10d10) lightning damage on a failed save or half as much damage on a successful one.