A bright whitish-gold golem sits in the center of a room, legs crossed, body literally aglow. From its eyes shoot harmless beams of light, 1 for each party member, even if it has to use multiple beams per eye or get its eyes crisscrossed. Its body remains in the room, but its eyes follow them like a hawk no matter where in the room they go.
The first time it is attacked in melee, it does nothing. The second time, it remains still for a second, then picks up the attacker and puts them a distance away from it, on their feet. The third time, and beyond, it throws the attacker across the room towards the way they entered from as hard as it can.
If attacked from a distance from which it can't reach them with its arms, the first time, it doesn't react. The second time, it intensifies the light to blind the attacker, and create mild warmth. The third time and beyond, if the attacker is in the light from its eye, it creates an explosion in the area of the attacker that is harmless to anything but the attacker.
It follows these procedures as best it can, even if attacked from outside the room.
Its body is highly resilient to most, if not all forms of damage, and if it is damaged, it regenerates large amounts of HP per turn.
If defeated, it simply collapses, and stops glowing, and by extension, stops illuminating the room, leaving it rather dark.
It can easily be walked around to reach the door to the next room and all it will do is stare at them with beams of light.