(meteorobs) Long path meteor -spiraling- *Magnified*

[Pat]

There are aerodynamic shapes that could cause spiraling. A cone, triangle, sea snail shape, one with a certain pattern of holes. Most of those would still be about a path as wide as the meteor...so you would not see the deviations.
I think many that appear to spiral are because they are an odd shape that is heated asymmetrically and they are tumbling or rotating. As the heated section rotates to face the observer it brightens then as the heated section rotates behind a colder section it dims. This can cause a spiral look, but the path would still be a straight line.
A true spiral that visually deviates from a straight line would require a very unstable aero shape with holes or a trough which (as Chris points out) would quickly ablate. But an odd shaped Iron meteor (say a wedge with a sloping hole) could theoretically spiral not on a straight path.