Mark Jeffrey Santos (also known as Mr. S or Mister Sasquatch) was born in Manila, the Philippines, in 1990, where he lives and works. With an early background in film and video production, Santos later brought his cinematic sensibility to visual art and has been actively exhibiting since 2015. His practice centers on richly imagined, dreamlike fantasy worlds populated by wide-eyed protagonists and colossal creatures embarking on fantastical journeys. Drawing on Pop Surrealism, popular culture, childhood memories, and personal experience, Santos has developed a distinctive visual language through imaginative world-building and character design.

Santos has exhibited in Taiwan, China, the United Kingdom, Singapore, Italy, and the Netherlands. Selected solo exhibitions include AWED by Mr. S at SIXINCH Gallery, Manila (2016); Reflections at Galerie Stephanie, Manila (2022); and Place of Solace at Dorothy Circus Gallery, Rome (2024).

In 2024, Santos participated in Asian Influence at STRAAT Museum in Amsterdam, where he created the monumental mural Drifting on Water. The work is now part of the STRAAT Museum collection and remains on public display.