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 .
Eosinophilic esophagitis
GERD
Radiation esophagitis
Carcinoma esophagus