We’ve all known people who fall asleep quickly. But Mable puts them to shame. This cute 5-year-old bearded collie mix suffers from canine narcolepsy. The most noticeable — and frightfully odd — sign of this rare disorder happens when a dog gets excited. She’ll typically go from being super excited to looking like she’s fallen into a deep sleep in an instant. As the owner of Mable describes it, “…like she’s been struck by a bullet.”

Sometimes the sleep of collapsed narcoleptic dogs is real sleep, but often the excited narcoleptic dog collapses into a catatonic state — one where she is awake, and aware of what’s going on around her, but utterly unable to move. The catatonic dog loses all muscle tone, much as happens to humans and other mammals in normal REM-stage sleep. (When you’re sleeping, that’s OK. Not so when you’re driving on the highway.)

The adorable Doxie mix in the second half of the Stanford video below is a textbook case of the floppy wet noodle quality of catatonia. She’s apparently fully aware of being like a rag doll, but can do nothing about it. Poor little pup! At last she’s in the very knowledgeable and gentle hands of Dr. Emmanuel Mignot, probably the world’s foremost expert in the field.

The next (and last) video of a narcoleptic dog is a heartbreaker. Skeeter struggles to resist sleep/catatonia, fights it valiantly, knows what’s going on, and can’t win. It seems to make his life a wreck.

There’s not much that can be done for narcoleptic dogs yet, although some tricyclic antidepressants may be of limited help. Some dogs have mild cases that don’t interfere too much with life, but for others, like Skeeter, it makes for a miserable and exhausting existence.

You can read more about canine narcolepsy and its genetic links in this K9 Perspective article. Check out this easy-to-understand article from Science News about narcolepsy in general, should you want to learn more.