The Subway Smasher is a guardian of one of the shards of the Relic of Nilhe. As the junior team and Geoff make their way to the Firehouse, the magnetic attraction of the Smasher's shard and the team's shard awakens the Subway Smasher. Ruptures erupt in the streets and sets off the P.K.E. Meter until the Smasher appears at the surface and attacks. It can breathe fire, body slam, and vomit Slime Crawlers. When the junior team defeats it, the Smasher loses sentience and collapses on the street. After performing a victory dance, the team finds the second shard of the Relic.
Defeating the Subway Smasher will earn the "Rush Hour Revenge" Achievement worth 20 points.
- The Subway Smasher is the only boss that doesn't return in Level 11: Parkview Retribution.
- It should also be noted that the Subway Smasher is very similar to the possessed subway trains found in The Real Ghostbusters episode "Knock, Knock".