It’s hard to believe, but today marks 15 years that the loveable river monster has been high-fiving fans, showing off his dance moves, and cheering the Senators on to victory.

The team’s website explains how Rascal came to be:

Back in April of 1998, a mysterious crate was found on the banks of the Susquehanna River on City Island near Harrisburg. The Senators’ front office had no idea why the crate was there and what it contained. To make sure the crate was safe, it was shipped to North Carolina where it was examined by marine biologists. Deemed to be safe the crate was returned to Metro Bank Park where it was opened on May 16th of that year. In the crate was a river monster, friendly and loveable…. Rascal was born!

Here are some pictures of Rascal through the years…