In the books:

• the main characters are 12 in the first book

• Annabeth is blonde with gray eyes

• grover is Caucasian

• in the lightning theif, the main characters hitch a ride with some animals

• Percy gets turned into a guinea pig in the sea of monsters

• the mist is something that always conceals magic from mortal eyes

• Percy knew Tyson before Tyson came to camp halfblood. He just didn't know he was a cyclops.

• nectar is the drink of the gods

In the Movies

• the main characters are 17 in the first movie

• Annabeth has dark hair and blue eyes

• Grover is African-American

• no percy guinea pig

• no rides with animals

• the mist is a spray on substance in a bottle

• Percy meets Tyson at camp Halfblood

• nectar is something both tyson and grover order in their coffees