Abstract: A adjustably-sized convertible bag, cover and protective barrier device includes a primary, barrier panel construction and a secondary, pouch-forming construction. The secondary panel construction is attached to the primary panel construction, and the panel constructions cooperatively form a scoop-like cap adapted to engage the upper portion of a seat. The device may be folded into several orientations: a bag orientation having an adjustable main interior compartment; a seat cover orientation adapted to adjustably engage the upper portion of a seat; and a mat construction adapted to allow an individual to rest upon various surfaces without becoming wet, dirty, or sandy.