You will need a pocket chart or something similar for this activity!
Give every student a pencil, make sure to mark it in a specific way so you know it is a exact pencil. Explain to the students that this will be the only pencil they can use in class. I put their classroom number and some washi tape on it. Place all of their numbered pencils in a pocket chart. Explain that you will check in with them each day to make sure they still have their pencil. If they have lost/ misplaced or misused their pencil, their numbered pencil is taken out of the pocket chart.
At the end of the challenge (you decide how long you would like to continue it) treat your kiddos who have kept their pencil the entire time.