I've never noticed anything particularly odd or different about Paul Rudd's nose. It's not too big, it's not too small, but to be perfectly honest- this is the first time I have ever thought about his nose at all. In Neil LaBute's The Shape of Things (2003), Paul Rudd's character wears glasses and his hair falls over his forehead. His nose looks huge. If it's some sort of prosthesis, it looks amazing. Like Martin Landau as Bela Lugosi in Ed Wood amazing. But if they just used the glasses and his hair style and lighting and other tricks to change the shape of his nose, then that's pretty remarkable as well. One thing that is worth mentioning is that Paul Rudd is acting along side the beautiful Rachel Weisz, so maybe that contributed to the illusion.
The question about his nose is answered in the film and I won't answer it here. But Paul Rudd's appearance and his quirky mannerisms are crucial to the development of the story. Paul Rudd plays Adam Sorenson and Rachel Weisz plays Evelyn Ann Thompson. They meet in an art museum where Adam works. She has stepped over the velvet ropes to photograph a statue of a nude with a fig leaf over the crotch. He approaches her to try and stop her, but they get wrapped up in a long conversation. She admits that she intends to deface the statue and he eventually agrees to look the other way, but first he gets her phone number.
The pair begins to spend a lot of time together. Adam's friends Phillip and Jenny, who happen to be an engaged couple, notice changes in Adam, both physical and inward. One night when the two couples are spending an evening together, Evelyn blows up in a rage leaving the other couple stunned. But later, when Jenny notices the changes in Adam, she seems to think Evelyn may be a great influence. Jenny follows that up with trying to make out with Adam.
The writer and director of The Shape of Things is the one and only Neil LaBute. He adapted the story for the screen from his own stage play. The play has the same name and the film features the same four actors that were in the original stage production. LaBute is a great playwright, one of the best, and his films usually have a play-like quality. Dialogue is the most important thing and he uses it to show the flaws in his characters. But sometimes, and this film is a great example, his characters seem to behave in a deliberate and intentional way that cause others pain. This is not a character flaw, this is just evil. The outcome packs a similar punch to LaBute's In the Company of Men (1997) but this time the audience is not in on the joke. We are just as blindsided as the victim. But the film does a great job of setting up the sense of impending doom that is sure to come. No one seems to be very trustworthy and someone, maybe several people are going to get hurt.