A movie theater in Seattle had to be evacuated on Friday after a box of mysterious fluid showed up in the mail.

The manager of the NorthBend Theatre opened up a box when it arrived, not noticing the label that said "Highly Contagious Human Substance."

The box began leaking liquid, so the staff called 911 who instructed them to evacuate the theater. The specimen was sent to a testing facility, and the manager was sent to the hospital as a precaution.

The box was marked to be sent to a medical facility over 40 miles from the movie theater. The Fire Department and postal office are unsure how the box was delivered to the wrong address.

The theater was reopened the next day.

Read more at NBC News