To steal or take a person's beer, sometimes done by an aquatic attack
dude I commanbeered so much at the last party i went to
We tried to commanbeer steve, but his friends prevented our attack
To take possession of beer left in your fridge for over a week. Typically done with beer left over from a party.
Brad: Dude, where'd my beer that I left from that party two weeks ago go?
Blake: After one week of being left in my fridge I commanbeered it and drank it.