Crystal-possesed half orc

Aggressive. As a bonus action, he can move up to its speed toward a hostile creature that it can see.

Multiattack. Half orc makes two attack with pickaxe, crystalbolt, or he can combine them.

Pickaxe. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 9 (1d12 + 3) slashing damage

Crystal bolt. Ranged Weapon Attack: +5 to hit, reach 5 ft. or range 60/120 ft., one target. Hit: 6 (1d6 + 3) piercing damage. If crystal bolt hits, its victim must make INT/WIS saving throw - DC 10 or it suffers Crystalic infection. 

Crystalic infection. At the start of each turn creature suffers: 1d6  poison damage, and its speed is halved as its blood begins starts crystalize. Each turn creature can do INT/WIS saving throw - DC 10. On fail, creature gain 1 stack of Crystalic infection. If a creature has 3 stacks of Crystalline Infection it becomes possessed by a crystal. A Crystal-possessed creature cannot be healed or dispelled and loses sanity and begins randomly attacking creatures around it.