How to kill beholders in three easy steps
1. Get the Shield of Balduran
2. Give it to your best tank
3. Chop up some beholders
You can also do it the hard way (like me) which involves the summoning of the beasts, undead and other beings. Then cross your fingers and hope really hard that not everyone will get killed
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The last arrow of Legolas kindled in the air as it flew,
and plunged burning into the heart of a great wolf-chieftain.
All the others fled. -J.R.R. Tolkien, The Lord of the Rings