If you have a soft spot in your heart for animals, you might want to pass on this one: United Airlines is investigating the death of a giant rabbit that had been stowed in the cargo hold of a flight from London to Chicago.

The three-foot rabbit named Simon was on his way to a new “celebrity” owner, reports The Sun, and was found deceased in the cargo hold when the flight landed at O’Hare International Airport.

“Simon had a vet’s check-up three hours before the flight and was fit as a fiddle,” Simon’s breeder told the paper of the 10-month-old bunny, adding that she’s sent rabbits “all over the world” without something like this happening before.

She says Simon was expected to grow even larger than his father, a four-foot giant named Darius, and snare the title of world’s largest rabbit.

United, which has suffered weeks of bad publicity after a passenger was forcibly removed from his seat and dragged off a plane, says it’s “saddened” by the 10-month-old rabbit’s death, and is now investigating.

“The safety and well-being of all the animals that travel with us is of the utmost importance to United Airlines and our PetSafe team,” United said in a statement. “We have been in contact with our customer and have offered assistance. We are reviewing this matter.”

Unfortunately, animal deaths on planes are not uncommon: According to U.S. Department of Transportation [PDF] data from 2015 — the most recent numbers available — domestic airlines reported 35 animal deaths, with 14 of those deaths happening on United flights.

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