What fascinated you when you were a kid? What ideas snuck into your mind, keeping you from sleep? For photographer Marcus DeSieno, that childhood infatuation revolved around what he couldn’t see.

“My brother was babysitting me and he brought home the movie Alien. There’s the premise that an alien is gestating in a human stomach and pops out and terrorizes people. That developed a fear of these invisible monsters, the idea that something could be living inside me. I carried that over into adulthood and then decided one day that it would be interesting to confront this fear,” DeSieno says.

He has moved on from aliens, and DeSieno now focuses on the very real organisms that can indeed host themselves