Christopher Eccleston's invisibility-empowered character says that he is like Claude Rains, which is a reference to Universal Studio's classic film, The Invisible Man (1933).
This episode marks the first time that we see Niki slip into Jessica mode in front of our eyes. Usually the transition is achieved through mirrors; here it is all done via Ali Larter's performance.
When Noah Bennet inspects Sylar, he talks with a physician, another employee. This is Hank - played by Colby French - who visited the Bennet family in the role of Claire Bennet's biological father six episodes before.
Christopher Eccleston's character exclaims "Fantastic". This is most likely a nod to his character as The Doctor in the long running BBC series Doctor Who (2005).