My pet lab has a habit of takin n keepin slippers with him like a cobbler.how to stop him frm doing dat?:(?

He is a mix of labrador and golden retriever..Gigantic,smart and obedient he is but when he is very happy,he takes slippers and runs around...if any slipper goes missing,its definitely with him or in his place..matured one still behaving like a baby...dunno wat to do to make him stop this habit :(