A dark, shadowy Spider-Man lunges forward. He stares straight ahead, arms raised, muscles flexed, poised for a fight.

Spider-Man has only half a leg, but Securitas guard Jhonny Augustin is working diligently on filling it in.

A popular figure among students with classes in the Walker Building, 24-year-old Augustin mans the security desk at the Boylston Place entrance every weekday morning. Anyone who walks past him has probably seen his work, the expertly sketched comic book characters who seem to leap off the page.

“‘What the hell are you doing here? You should go to art school.’ That’s one that I hear a lot,” Augustin said of the most frequently asked questions he fields from curious students. “And ‘Why don’t you use color?’ I’m partially colorblind, so I try to stay away from color.”

He said he might add some red to his current Spider-Man work in progress, his favorite character to draw, but he usually gives the finished sketches to two of his younger sisters to color in as they’d like.

An avid artist in his spare time, Augustin spends his days as a Securitas Security guard, while he works toward his master’s degree in criminal psychology at University of Massachusetts-Boston.

“So many people talk to me about [going to art school], and I guess it wouldn’t hurt to take a class or two,” he said.

His brother is a lawyer, and he has two cousins who are cops. Another cousin is in the army. “Before I even had a chance, I had psychology forced on me. I enjoy it though. I’m not hating on it. My brother always jokes that I’ll draw for the FBI or something.”

While becoming a forensic sketch artist may seem logical, Augustin said there may be one hang up.

“I suck at drawing real people,” he said.

Born in Haiti, Augustin moved to Florida when he was four and has been living in Boston for about 10 years. “I’ve been drawing forever,” he said.

He credited his artistic beginning to a lack of action figures as a child. “When I was little I never really got toys to play with, but I watched a lot of cartoons,” he said. “I was that kid who woke up at 6 a.m. just to catch that first cartoon on a Saturday morning.” He recalled watching Teenage Mutant Ninja Turtles, drawing the characters and cutting them out to use them as toys.

“I was also a huge comic book reader back in the day,” he said.

He drew his favorite comic book and cartoon characters all through his childhood, but lost his love for the hobby in high school. “But then I got this job, and I just sit at the desk so I draw,” he said. “They don’t let us bring laptops so I can’t really do homework or anything.”

Each piece would only take him about an hour or two if he could really sit down and get into it, he said, but with distractions and conversations at work, he usually takes a few days to finish a sketch. Some of his work, depending on the size, may take longer.

And yes, he does take requests.

Last month he completed a huge drawing of the Avengers with four large-scale characters for a faculty member.

The Spider-Man he is working on now was promised to a friend and he is starting a Wonder Woman drawing for another friend, both Emerson students who saw his work in passing and wanted a piece for themselves. He said he usually draws them free of charge.

“I find this as fun,” he said. “I give them a couple of out, though. If they keep saying ‘Take it,’ then I’ll take it.”

Also by request, Augustin draws tattoo designs for friends and co-workers. He drew one for his boss of praying hands, noting that hands are among the hardest things to draw for him. He said some of the desired designs were a little weird, such as one of devil skulls and another of an African queen with muscular men surrounding her on a throne.

“I don’t draw a lot of girls, and I get some criticism for that. [But] I did draw one girl and I got a hard time for that too,” he said. “Like, ‘The boobs are too big, the boobs are too small.’ But these are superheroes. Everything is huge.”