There’s a group of mummies in Mexico you may not want to go see. Even though they remain on display in Mexico City—and have routinely traveled the country as part of exhibits—not everyone in the country deems them safe.

Unlike in the movies, there’s no threat of these mummies coming back to life. Instead, the unexpected life causing problems here is of the fungal variety.

Mexico’s National Institute of Anthropology and History says the appearance of fungal growth on the traveling display is causing concern about the way the mummies are handled and presented to the public.

See Also:

Manuscript containing missing details of Ptolemy’s Meteoroscope decrypted

Known as The Mummies of Guanajuato, the exhibit made an appearance in the United States in 2009. But it was a recent exhibit in Mexico City, showing off six mummies in glass cases, that has led the institute to alert the public— especially considering that they don’t know how airtight those glass display cases really are.

Read more: Popular Mechanics