A magic warhammer of dubious craftsmanship, Thunderstrugk seems like a knock-off version of a line of sought-after warhammers made in the Forge of Spells, and it tends to harm the wielder almost as often as it damages opponents. Its shaft is inscribed with dwarven runes that glow blue when the hammer is grasped. To activate its enchantment, use a bonus action, whirling the hammer in an arc three times and speaking the dwarven word for "Engage." Using another bonus action to speak the word dwarven word for "Cease" deactivates the enchantment.

When attacking with this weapon, you cause 1d8 bludgeoning damage on a hit. But when the enchantment is active, roll a second d20 in addition to the attack roll. Regardless of the hit, the second d20's roll adds one of the following effects to the action:

1-2 Wielder suffers 1d4 lightning damage and 1d4 thunder damage

3-4 Wielder suffers 1d4 lightning damage

5-6 Wielder suffers 1d4 thunder damage

7-10 Nothing happens

11-13 Add +1 to attack and damage rolls

14-15 Add 1d4 lightning damage 

16-17 Add 1d4 thunder damage

18 Both wielder and target take 1d4 lightning damage

19 Both wielder and target take 1d4 thunder damage

20 In addition to regular crit bonus to damage, add +1 to attack roll, as well as 1d4 lightning and 1d4 thunder damage.

 

Proficiency with a Warhammer allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: To attune to this weapon, the wielder must spend half a short rest meditating on it, the remaining half practicing with it., Versatile, Push