Feline esophagus is:

Ref. API Textbook of Medicine. Pg. 1690   Feline Esophagus Feline esophagus also known as oesophageal shiver ,refers to the transient transverse bands seen in the mid  and lower esophagus on a double contrast barium swallow . The appearance is almost always associated with active gastro-esophageal reflux and is thought to be due to contraction of muscularis muosa with resultant shortening of the esophagus and "bunching up" of mucosa in the lumen .