Sure, glass jars are pretty. But one family in London is warning others against using empty jars as decoration after rays from the sun refracted off a Nutella container in a windowsill, starting a blaze that engulfed the home and killed their beloved pet.

Investigators with the fire brigade believe it’s those concentrated rays of sunlight that started the fire, reports the Associated Press.

The jar was sitting on the daughter’s bedroom window sill, holding her loom bands, when low winter light was focused through the container and sparked the fire, reports GetWest London.

It took four fire engines and 21 firefighters to put down the blaze, which destroyed the roof and did some serious damage to the first floor.

The family was out at the time, but their Jack Russell terrier was trapped inside the home and died from smoke inhalation.

“We’re all heartbroken at Chili’s death and we’ve been told it will be up to a year before the house is ready for us to move back into,” said the father. “I want to ensure other people are aware of the dangers and know to keep glass items away from windows and out of direct sunlight so they don’t have to go through anything like this.”

Warning after Nutella jar sparks devastating blaze [GetWest London]

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