Police are investigating a small subway explosion that happened last week in Bedford-Stuyvesant.

According to police, the blast occurred last Thursday during the morning rush at the Nostrand Avenue station. They say it appears that vandals left a metal object on the track, then stood back to film as a C train entered the station.

The explosion was first shared by the blog Gothamist.

Some residents said the incident is not as scary as it is sad that someone would do this for fun.

The MTA told News 12 in statement, "If this video really depicts what it claims, it is unconscionable that vandals would have deliberately endangered the lives of our customers and employees, as well as delayed thousands of customers during the morning rush."