Portuguese man o' war
The Atlantic Portuguese man o' war lives at the surface of the ocean. The gas-filled bladder, or pneumatophore, remains at the surface, while the remainder is submerged. As the Portuguese man o' war has no means of propulsion, they move according to the winds, currents, and tides. Although they are most commonly found in the open ocean in tropical and subtropical regions, they have been found as far north as the Bay of Fundy, Cape Breton and the Hebrides.
Motion (gridiron football)
The purposes of motion are to allow the offense to change formations, and to gain clues about the defensive playcall, particularly whether the play is "zone" or "man-to-man" coverage (typically, a defense playing "man-to-man" coverage will have a single defender follow the offensive man-in-motion across the formation, whereas in a "zone" defense, as the man-in-motion travels across the formation, which defender is assigned to cover him will change, causing the entire defensive formation to shift to accommodate the modified coverage assignments), which can often cause the offensive team to modify its own playcall, using an audible, to a play that is better suited to defeating the defense's strategy. In leagues that allow forward motion, motion can offer a chance to gain momentum on the defenders.