Trapped!

You dodge the fireball, but are amazed to see the skeleton teleport in front of you. "How is this happening?" you scream to yourself.
Suddenly, Robert perks up. "He must be the corpse of a mage from ancient times," he says to you.
"Well, this sucks," you cry out, blocking a barrage of powerful blows. Suddenly, you see his weakpoint. ON HIS NECK IS A CRACK IN THE BONE!!! However, you feel that this would not be that obvious. However, it's all you got.