Where does he come up with this stuff?

Every night Mavic climbs up to the top bunk to hang out with Hunter and every night we have to go in and get him down.  Last night was no different, the boys were getting rowdy so Spencer went in to get Mavic out of Hunter's bed.  The difference with last night was what Mavic said.  When Spencer said he needed to get down Mavic responded by saying, "You have won this one".  Where did he even hear this?  He is always surprising us by his funny ways!