After a hole opened in a street this week it was found to be filled with a lime green liquid that seemed to glow.
No worries though, it turns out this is standard procedure.
The hole has been covered now bringing a kind of boring end to a story that could have involved Raphael, Donatello, Leonardo and Michelangelo.
When a sinkhole opens crews in Philadelphia add a fluorescent dye to the water in order to better be able to trace the break.
That allows them to more quickly make repairs and get things back to normal.
Or at least a giant alligator.