Fang of the Thunderbeast

This jagged spear, made from the fang of a legendary sabertooth, crackles with the power of storms. When you hit a creature with this spear, you can expend one use of its magic to deal an additional 1d6 lightning damage. Additionally, once per long rest, you can use the spear to cast the Thunderwave spell (save DC 13) as a single action, without using a spell slot. The spear also grants you advantage on attack rolls made against beasts. A faint glow surrounds the spear during storms, giving it a +1 bonus to attack and damage rolls in such weather conditions.