Miss Petunia

Miss Petunia, the Bathing Beauty, is a portrait ghost of unknown age. She was the "Miss Ghost" runner-up from six years before the appearance of Luigi's Mansion in Boo Woods. Apparently, she hasn't done much modeling work since and has gained a lot of weight. In fact, besides being overweight, she also has pig-like features, including a pig snout, hooves for hands, and a pink hue. Wearing her showering cap and bathing suit, Miss Petunia spent her time in Luigi's Mansion taking showers in the Bathroom on the second floor. Ultimately, she was captured by the heroic Luigi during the search for his brother Mario.

When Luigi first entered the Bathroom on the second floor, he noticed the voluptuous silhouette of a woman behind the shower curtain. Luigi, being the curious fellow that he is, decided to pull back the curtain with the Poltergust 3000 to get a better look. To his dismay, the figure was not a stunning woman but the obese Miss Petunia. Angered that Luigi opened her curtain, Petunia shot a blast of scalding hot water at the peeping tom, delivering ten HP of damage. She then went back to her shower. Luigi decided to give her a blast of ice, provided from his newly acquired Ice Elemental Medal. The ice caused Miss Petunia to sneeze, making her vulnerable, and Luigi sucked the ghost in with the Poltergust. Although she strongly tugged in an attempt to escape, Luigi eventually won the battle and captured Miss Petunia. After capturing the porcine portrait ghost, Luigi acquired the key needed to open the door to the Billiards Room.

Trivia

 * According to Nana's diary, the grandmother ghost once played a practical joke on Miss Petunia by filling her bathtub with ice while the former "Miss Ghost" runner-up was away. When Miss Petunia returned to her bath, she was in for quite a shock. This diary entry gave Luigi a clue on how to capture Petunia during the events of Luigi's Mansion.
 * The Looney Toons character Petunia Pig may have been the inspiration for Miss Petunia, who is similarly-named and resembles a pig herself. However, this has not been confirmed and may just be a coincidence.