There is an exploit which allows you to auto attack the year beast without him being able to attack anyone in your team. The only thing you need is someone to pick visage and level his ultimate. Have your entire team hide in the corner of the map as the Year Beast spawns. After he spawns have visage's familiars fly in the trees behind the secret shop, in the corner of the map. This will make the Year Beast try to reach them and effectively do nothing, allowing you to do all the damage your heart can desire.
This is sure to be quickly patched and fixed so if you want to see this hilarious way to best the beast, try it now.
Edit: This exploit has been patched and no longer works.
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