A Jonathan is a clear plastic water bottle of any size filled halfway or all the way with water, stuffed with basically any piece of plastic or paper or dirt you can find and held as a keepsake. You shake it and just bring it around with you.

Walking to a job interview? Bring your homemade Jonathan with you. Funeral? Jonathan's coming with you too.

Some ideas of materials to put in your Jonathan include moldy bread, anti-brain zap tablet boxes, or anything you can find. You can purchase ready-made Jonathans in Argos.