Here's proof that you need to be very careful what you write on social media.

Justin Carter, of Austin, Texas, is currently in jail after he sarcastically wrote on Facebook that he would blow up a school while he was in a dispute with someone over the online game League of Legends.

Carter was 18 when the incident happened in February.

His father, Jack, summed up the incident:

Someone had said something to the effect of 'Oh you're insane, you're crazy, you're messed up in the head,' to which he replied, 'Oh yeah, I'm real messed up in the head, I'm going to go shoot up a school full of kids and eat their still, beating hearts,' and the next two lines were lol and jk."

Nobody was laughing at the joke, though. A Canadian woman spotted the post and called police, who hauled Carter to jail on March 27. It seems the woman found Carter on Google and she became concerned when she discovered he used to live near an elementary school.

Carter was charged with making a terroristic threat and could get eight years behind bars.

The timing of Justin's remarks were pretty poor, considering he wrote them shortly after the massacre in Newtown, Connecticut. His father said his son was oblivious, noting, "Justin was the kind of kid who didn't read the newspaper. He didn't watch television. He wasn't aware of current events. These kids, they don't realize what they're doing. They don't understand the implications. They don't understand public space."

Justin's family and friends have rallied to his side to help free him.

What do you think -- is this an overreaction or does Justin deserve to go to jail? Watch a news report on the teen below.

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