This is not a doodle, it is a noodle. Because the upper barrel fires noodles and the lower barrel fires cocoa puffs. Ha ha, everyone always wants to know all the details on these gun sketches even when they were just random paintings. Sometimes the artist might be painting a weapon that has a specific backstory and details etc., but there is something to be said for just searching out cool shapes for fun.
And while I'm not sure what it fires, the design doesn't look very friendly for a standard bullet magazine and the barrel's a bit complicated, so I'm gonna guess primary fire is a plasma pistol and secondary fire is a shotgun or sonic burst.