Wood Giants are presumably the result of a tree waking up and attending the gym while taking steroids. Not that anyone has ever seen a Wood Giant in a gym, but what else could explain their gigantic frames and bulky limbs.
Regardless, they are solitary creatures that roam the forests of the Overworld, dominating others in the area and maintaining their rule over the trees.

They seem capable of both growing and discharging their wood-like skin at will, to devastating effect on attackers.
They keep a heavily-fortified and resilient form of wood armour over their body, which acts as an incredibly effective damage mitigation technique.
Once sufficiently broken down with blunt-force damage however, they will violently eject the layer towards the attacker, causing intense lacerations that can easily cause a victim to bleed out.
They will then begin to regrow the layer over time, restoring their natural protection and increasing their survivability.