The ceiling for magical cars apparently stops at "public transportation that does a spatial trick." In Harry Potter, it was a flying car and then a compactable double-decker bus. In Percy Jackson, we get a busted taxi that magically splits in half while going at suicidal speeds to gain an advantage that we assume must exist but cannot begin to be explained.
There's Even a Transformer (Transformers, Hellboy II)
Because mythological creatures and teenagers with godlike powers apparently aren't impressive enough, Percy Jackson tosses us a shape-shifting robot (a golden one, of course -- it is magic, after all). The filmmakers are clearly filching from every PG-13 blockbuster from the past decade. They might as well throw in a kraken while they're at it.
There's a Goddamn Kraken (Clash of the Titans, Pirates of the Caribbean)
The kraken has appeared in more movies over the past nine years than Clint Eastwood, and the Percy Jackson version manages to rip off Pirates of the Caribbean 2 and 3 by combining a cataclysmic whirlpool with a tooth monster. While no one in the trailer actually says the word "kraken," we're staring into the gaping mouth of a sea monster in a movie about Olympian gods. It would almost be worse if it wasn't the kraken, and just some cheap knockoff like "the graken" or "the cracken" or "Squid-ules" (like Hercules, only in the ocean). Also, while we can't tell for certain from the trailer, we're going to assume that monster is made of gold.
David can be found over at Film School Rejects and on the Twitter.