Instructions
Play through "LIMBO" until you reach chapter 6, which deals exclusively with the spider boss. The first thing you will notice is a bear trap in a tree.
Walk up to the spider to entice him to attack you.
Dodge the spider's strikes. The spider's only strike is raising a leg and slamming it into the ground. Move away from the leg to avoid its strike. When he hits the ground, the world will shake, causing the bear trap to fall onto the ground.
Push the bear trap toward the spider, placing it wherever his leg is about to hit the ground for its next strike. Instead of hitting the ground, the spider's leg gets caught in the bear trap for a few seconds, taking damage from it before he shakes it away.
Repeat step 4 until you defeat the spider.