Beamos is a recurring enemy in the Legend Of Zelda series that is generally stationary and shoots a beam from it's eye at Link that will do damage upon contact.
 The Legend of Zelda: Skyward Sword
In Skyward Sword Beamos are first introduced in the Lanayru Mining Facility and can only attack if reanimated by a Timeshift Stone due to their existing in the past (beamos may come in single or double pillar size).
It's weakness is it's eye and it can be reached by cutting a blue line that is on the pillar holding up its head horizontally and then quickly stabbing it in it's eye before it can attack. Alternatively, later on Link can dispatch of it much quicker by shooting it's eye with the Bow.