The first time you notice your dog slowly creeping beneath a low-hanging branch or a dangling tablecloth, head moving languorously side-to-side and a far-away look in his eye, you might worry that it heralds a seizure, or points to obsessive-compulsive tendencies. But once the pup has performed this ritual repeatedly with no apparent ill effects to health (his) or property (yours), you may simply wonder what causes this hypnosis-like behavior.In fact, experts say that Trance-like Syndrome (TLS)—also referred to as “ghost-walking,” “weed-walking” or simply “trancing”—is usually a benign canine quirk. Though most common in Bull Terriers and sighthounds (such as Greyhounds and Salukis), TLS has been observed in multiple breeds and mixes.But why do our furry friends act this way in the presence of low-hanging objects, and are there any situations in which this ritual indicates an illness or behavioral issue?Experts refer to the manner in which dogs move while experiencing TLS as “hypokinetic gait,” an incredibly slow pacing characterized by soft, deliberate footfalls. This slo-mo walk seems to be stimulated by the dog passing under a plant or fabric hanging at head- or back-height. In some dogs, the sensation elicits a glassy-eyed gaze and affects the way they position their faces. “Their ears will be completely flat to the head, nose pointed up to the sky and eyes squinted,” explains Dr. Michelle Burch, DVM, with Safe Hounds Pet Insurance.