Trevor Henderson

Trevor Henderson (born April 11, 1986) is a Canadian illustrator, concept designer, and writer who rose to fame in the late 2010s through his work on Instagram. He is best known for his creatures such as Siren Head, Cartoon Cat and Cartoon Dog. He also wrote the teen horror duology Scarewaves, and in the fall of 2022, he created the horror podcast Mayfair Watchers Society,¹ becoming its chief creative director and mastermind.

Henderson was born in Toronto, Canada, on April 11, 1986. He currently resides in Toronto, where he actively pursues creative pursuits and posts his work on Instagram. Trevor Henderson graduated from the OCAD University.²

His early work in 2012 was in the acid body horror style, from which he moved on to his own recognizable style.² The artist's work is unique in its "Unnerving Images" style, which involves creating eerie creatures over real images. In interviews, Trevor has often spoken of his love for the Found footage genre, which creates the impression that what is shown on screen is actually happening in real life.³

When he started his artistic journey in 2018, Trevor Henderson says he drew monsters every day using photos people sent him online.⁴ Until 2020, Trevor combined painting and working in retail. According to the artist, his last attempt was at a bookstore, which he left two months before the start of COVID-19 pandemic, to completely switch to freelancing.⁴

Having gone freelance, Henderson began expanding his scope of work in the early 2020s. In the fall of 2022, he launched a horror anthology audio podcast called Mayfair Watchers Society in collaboration with the renowned horror network Bloody FM.¹ The project is based entirely on the creatures and ideas of Trevor Henderson. As of 2026, over 70 episodes have aired, each featuring terrifying creatures in the fictional town of Mayfair.

In late 2023, he wrote the first installment of a young adult horror book series, Scarewaves, which was entirely written and illustrated by the artist.¹ On August 5, 2025, Trevor released a sequel, Scarewaves: Beyond the Grave.¹ Trevor Henderson has illustrated over 20 horror books.⁵ Henderson's illustration work has garnered recognition in leading national media outlets; in 2024, The New York Times singled out his artwork for the horror novella Stay on the Line.⁶

One of Henderson's most recognizable characters, Siren Head, was created in August 2018. The creature's main concept was a cryptid embodying the numbers station phenomenon, which was of great interest to the artist at the time.⁴ The monster first appeared on Instagram on August 19, 2018. Trevor himself, recalling the first few days after its publication, noted: "It got a couple of likes. People were like, 'This design is really cool,' and then nothing happened for six months".

Siren Head is a 40ft (12m) tall humanoid monster, with its body consisting of rusted metal and mummified skin. It has two functioning sirens in place of a head, with some depictions having human like jaws and teeth, and a snake-like tongue within the sirens. Siren Head is known to be very dangerous, it is an apex predator that uses sound to attract prey. It’s sirens often blare garbled music, Emergency Alert System broadcasts, and people speaking or screaming for help. Siren Head can also mimic voices to lure hikers, campers, and even children to lure prey to the noises.⁴

The character was first noticed at the end of 2018, when an acquaintance of Trevor Henderson asked for permission to create a small video game featuring Siren Head.⁷ It wasn't until April 2020 that a video of a giant Siren Head towering over a city went viral on social media. Some time later, the 2018 game was later spotted and quickly picked up by video bloggers.⁴ As Trevor noted, the creature's popularity wave lasted for about 4 months, and during this time he was everywhere.⁴

In 2020, the idea of including the creature in SCP Foundation canon was also actively promoted, but Trevor responded to this proposal: "I really like it. There’s a lot of great stuff there. But once something gets put on the SCP Foundation website, it becomes Creative Commons licensed. So, in a sense, it becomes public domain. So, trying to spread misinformation about Siren Head [being part of the SCP project] is kind of a way of taking this character away from its creator".⁴

In 2026, it was announced that a Siren Head movie adaptation was in development from Warner Bros., with Brian Duffield directing, Zach Cregger writing, and Henderson serving as Executive Producer.⁸⁹

Cartoon Cat first appeared on Trevor Henderson's Instagram in August 2018, as a rubber hose style cartoon with large eyes, a toothy grin, and long limbs.¹⁰ Cartoon Cat is an ancient hollow rot that uses the collective human awareness and memories of old cartoons as a passageway to manifest into reality and wreak havoc. It is said to appear in abandoned places like malls, and has the ability to shape shift, have cartoon physics, etc.¹¹

On July 13, 2026, it was announced that Tristar Pictures had acquired feature film rights to Cartoon Cat, marking Henderson's second feature deal after Siren Head.¹¹