When exploring campy films, it's hard not to mention 1997's Batman & Robin. The sequel to Batman Forever maintains its neon aesthetic but ramps up its over-the-top performances. In the end, the film feels like an homage to the Adam West era of the Caped Crusader. One of the most iconic villain performances comes from Uma Thurman's Poison Ivy. That said, while it's hard to believe that her performance could be topped in terms of camp, she outdid herself as Medusa in Percy Jackson and the Lightning Thief.
In the film, Percy learns of his heritage as the son of Poseidon and begins to train as a demigod. However, when Zeus' lightning bolt is stolen, Percy is the first suspect. To prove his innocence, he is sent on a series of quests to find the culprit and enters into the lair of Medusa. In mythology, Medusa is a Gorgon with a head of snakes and a gaze that turns anyone who looks at her into stone. Certain interpretations, like this one, also show her as a seductive creature who uses her charm to lure in victims. It's this version that Thurman chooses to emulate to the best of her abilities.
While she doesn't have a grand plan in Percy Jackson, her villainy is still evident from the moment she arrives on the scene. In comparison, Poison Ivy wants nothing more than to eradicate toxic waste and give the Earth to her plants. Because she cares so little for humans, she feels freer to dress and act however she wants and treats them as her puppets. She also uses her powers to entice and control men to gain the upper hand. Because of the power trip and the tone, Thurman's outrageous acting style feels much more fitting in the already ostentatious Batman & Robin.
That said, the tone of the Lightning Thief is far more reserved. At its core, it's a family film about a young boy overcoming dangerous odds and reuniting with his father. Because of this, there isn't much room for camp or for the actors to chew up the scenery with outrageous performances. That said, Thurman's Medusa makes her mark by doing just that. Tapping into her inner Ivy, she uses the same seductive tone to try and compel Percy to look at her eyes. The snakes on her head also act as a substitute for her plants and show how she cares more for another species than humanity.
Though it has an air of cringiness surrounding the character, her performance fits well for the being she is creating. But with Lightning Thief's tone being more reserved, she sticks out like a sore thumb and detracts from the film's momentum. Where Batman and Robin feel like a competition over who can outmatch each other in corniness, Percy Jackson just makes Thurman's character feel more like the odd one out.
There's no denying that both Poison Ivy and Medusa are bad when put into the context of the films they appear in. But this is mainly due to too much acting or the wrong tone. In Batman & Robin's case, the story and setting only made Thruman's Ivy look more comedic than insane. But adding a similar performance to Percy Jackson and the Lightning Thief shows that even great actors can deliver campy performances that stand out when the tone doesn't match it.