I had a friend who always rode his bike with his pet rat perched on his shoulder. He let me try it too, and we had a great summer biking, losing the rat under the patio and coaxing it back out with some peanut butter, and getting into trouble for nailing our plywood fort to the side of his apartment. We were at that perfect age when the world is still entirely good, before puberty sets in and children mock one another for playing with rats or having the opposite sex as ‘just a friend.’