Interior of a micro-wormhole with gravitational eddies
A gravitational eddy was a force closely associated with the interior structure of wormholes. Surrounding the interior wormhole conduit, the eddies had a gravitational attraction that could pull objects into the aperture, or even crush objects that were caught within them. (VOY: "False Profits", "Eye of the Needle", "Hunters")
In 3196, Cadet Darem Reymi accidentally got the USS Athena's saucer section caught in a gravitational eddy and he couldn't get it out again. Commander Jett Reno was able to free the ship with minimal damage and explained that Darem couldn't compensate for gravitational shear because he was going too fast when Darem hit the eddy and then tried to stop. (SA: "Rubincon")