Trending badgeTrendingPosted 55 minutes ago21 Times Celebs Encountered Fans Who Overstepped Boundaries, And Some Of These Are Actually TerrifyingAriana Grande's recent brush with a clout-chasing fan barely scratches the surface.by Aaron AntBuzzFeed ContributorFacebookPinterestLink The term "stan" is frequently used in online culture, particularly when referring to specific fanbases and their subgroups. However, by the time Eminem released his hit record in 2000, there was a long list of people whose parasocial relationships with celebrities became dangerous. EminemVEVO / Via youtube.com Ariana Grande, who has dealt with tragedy and trauma throughout her career, has had a number of terrifying encounters with fans, including one recently at the premiere of Wicked: For Good in Singapore. @lanagrande / Via x.com In Ariana Grande's case, she was fortunate to have Cynthia Erivo and security intervene. Unfortunately, not everyone has managed to come out unscathed from fans who've obsessed over celebrities. Some instances have resulted in arrests, others in death. Overall, the lengths that people go to in order to get the attention of some celebrities are extreme. From Taylor Swift to Jodie Foster, below is a list of 22 times that celebrities have had terrifying encounters with fans. 1. Ariana Grande Jamie Mccarthy / Getty Images Ariana had to deal with a number of overzealous fans over the course of her career, but most recently at the Wicked: For Good Asia-Pacific premiere in Singapore, 26‑year‑old Australian Johnson Wen breached barriers and grabbed Ariana's arm as she walked the red carpet. Security and co‑star Cynthia Erivo intervened. Wen was later arrested and charged, though it was noted that it wasn't his first time running up on a celebrity. 2. Taylor Swift Raymond Hall / Getty Images Taylor has had more than one encounter with terrifying stalkers, but perhaps in this instance, "fan" might be a bit of a stretch. According to the Guardian, Julius Sandrock was arrested outside of Swift's Beverly Hills home on suspicion of stalking after police were called by her security. Authorities said that they found him with a knife, rope, ammunition, multiple masks, and gloves in his vehicle. Investigators say he drove from Colorado to Los Angeles to see the singer. A temporary restraining order was secured against him soon afterward. 3. Keira Knightley Gareth Cattermole / Getty Images In 2016, 49-year-old Mark Revill pleaded guilty to stalking Keira Knightley, but his attempts to get in contact with her were far more bizarre than frightening. Highbury Corner Magistrates' Court heard that Revill repeatedly visited Keira's London home, made meowing noises through her letterbox, drew chalk arrows pointing to her front door, and delivered letters and a USB containing cat-themed music he had composed. Prosecutors said his conduct caused "alarm and distress," and Revill admitted to stalking. 4. Justin Bieber Patrick Smith / Getty Images Bieber is another pop star who has had to face off against some intense fans. Dana Martin, a man serving two life sentences for the rape and murder of a 15-year-old girl, allegedly hired an uncle and a nephew duo from behind bars to kidnap, castrate, and kill Justin. The scheme proved unsuccessful as the authorities spoiled the uncle and nephew's plan. However, the affidavit revealed that Martin was a huge fan of Bieber, with a tattoo of the singer, and tried to correspond with him to no avail. This apparently motivated him to mastermind this failed scheme. 5. Lilly Allen Mike Marsland / Getty Images Less of a fan, and more of a foe who previously alleged the singer stole his lyrics, Alex Gray broke into Allen's home and stole personal items like a handbag, jewelry, money, a phone, and more. This reportedly only happened after he reached out to her on social media with offensive messages. The court found him guilty of burglary and stalking. 6. Sandra Bullock Karwai Tang / Getty Images In June 2014, Joshua James Corbett jumped the fence at Sandra's Bel‑Air home and broke in while she was inside. Bullock hid and called 911 as he walked through her house. Police arrested him on burglary, stalking, and weapons charges. Court records and affidavits show he carried love letters about her and magazine cutouts of her while police later found an arsenal of illegal firearms at his home. Corbett was sentenced to probation. 7. Madonna Dominique Charriau / Getty Images Unshockingly, Madonna has also encountered crazed fans, including Robert Dewey Hoskins, a stalker who scaled the walls of her Hollywood Hills estate and threatened the singer and her staff. During one confrontation, her bodyguard shot and wounded him as he lunged with violent threats. At trial, Madonna testified Hoskins told her he'd slit her throat if she wouldn't marry him. 8. Uma Thurman Hoda Davaine / Getty Images Convicted of stalking and aggravated harassment, Jack Jordan spent years stalking Uma Thurman. Jordan repeatedly showed up