Possible Clues:

• "An Inconvenient Truth" writer Al
• Bloodshed caused by acceleration of Irish gold, reportedly
• Violent movie feature
• Nasty ogre creating bloodshed
• Pierce with a horn; blood
• Bush with sharp spines: son's lost much blood
• Blood group often reported erroneously at first
• Stuff in a horror movie
• "An Inconvenient Truth" subject Al
• Slasher flick feature