CLEVELAND, Ohio - Terry Rozier, the Shaker Heights High School grad now running the point for the Boston Celtics, is scary good.

A backup, he stepped in for injured star point guard Kyrie Irving (remember that guy?) and helped Boston dominate despite missing its two biggest stars in Irving and Gordon Hayward.

When you watch the Cavaliers take on the Celtics in Game One of the Eastern Conference Finals in Boston Sunday, you are likely to see fans, maybe even players on the bench, sporting "Scary Terry" T-shirts.

It uses the name of a character on the Adult Swim animated TV series, "Rick and Morty." And it's a caricature of Terry wearing a "Scream" mask. There are a number of versions. The whole "Scary Terry" thing has gone viral in Boston.

And it was made in Cleveland.

Here's the story:

Rozier is represented by Mayfield Heights-based sports agency Verus Management Team, which has about two dozen clients, six of whom play now in the NBA. The firm's marketing guy, Clevelander David Mariotti, is all over social media looking to promote clients, the biggest of whom is Rozier.

When Barstool Sports podcast host Coley Mick slapped the "Scary Terry" nickname on Rozier, and Rozier loved it, Mariotti sprung into action. He noticed that the name was catching fire on Twitter.

Mariotti reached out to his friend, Cleveland artist Glen Infante, who owns the iLTHY clothing brand. Infante drew up a cartoon caricature of Rozier's body with a Jason mask from the Friday the 13th Movie. But Terry preferred the "Scream" mask based on the Edvard Munch painting. (The scream mask is among his many tattoos and "Scream" is his favorite horror flick.) Infante made the change.

Just before All-Star Weekend in February, Rozier wore the shirt. And "Scary Terry" started to take off. Now he's got "Scary Terry" shoes, too.

Boston Celtics guard Terry Rozier, who graduated from Shaker Heights High School, wears athletic shoes with his "Scary Terry" design during the third quarter of Game 5 of the team's NBA basketball playoff series against the Philadelphia 76ers in Boston.

"Boston loves it. They're embracing it," said Mariotti, who got some help in the marketing effort from Aaron Eanes and A&A Management Group.

It helps that Rozier is putting a fright into his opponents on the court and seems to be a master marketer off the court and on social media.

There's a "Scary Terry" store with a variety of apparel choices and many versions of the caricature, including a "Mask Off" one where Terry is holding his "Scream" mask and another where he's standing, masked, in a pile of red, white and blue confetti. That one pokes fun at the Philadelphia 76s, who released a storm of confetti when the Sixers Marco Belinelli tied Game 3 of the most recent series with a two-pointer that everyone in Philly mistakenly thought was a winning three. The Sixers ended up losing in overtime, and eventually lost the series 4-1.

Cleveland's North Water Productions has been busy making videos playing up the "Scary Terry" persona, which have been shared on Twitter by Barstool Sports.

Danny Young, principal at Woodbury Elementary School in Shaker Heights and Rozier's former High School coach and mentor, said he's loving the whole "Scary Terry" thing.

"The 'Scary Terry' thing is pretty cool. Hoodies, t-shirts, shoes," he said. "Even when I had him, you could tell really soon how scary talented he was. Around 10th grade you saw he had his potential to reach his dream of playing at Louisville. He did that and more and I am not surprised at his success."

Terry capturing the hearts of Bostonians, and filling Irving's big shoes, is no surprise, either.

"He's the kind of kid who seizes the moment when he has the opportunity," Young said, noting that he started on the junior varsity team at Shaker, but kept pouring in points every chance he got to play varsity as a freshman.

"And he's a good kid, man. He's a fun loving kid. Great smile. Charismatic," said Young. "It's pretty cool what he's doing in terms of marketing himself."

Infante is sure to be asked to create a new "Scary Terry" version for the Cavaliers series. Let's hope it's 'Scary Terry,' having played hard and acquitted himself well, saluting the victorious King.