Suddenly Seymour is standing beside you. Like, right beside you.

“Little Shop of Horrors,” which opened Thursday night off-Broadway, is getting a much more intimate staging than when it last played New York, both on Broadway and at the large City Center.

Tight feels right, because the roots of Alan Menken and Howard Ashman’s terrific show are in small houses. Now the insanely catchy doo-wop musical occupies the 270-seat Westside Theatre, with a bare-bones set and not a projection in sight. Freed from dealing with the usual trappings of modern musicals, you can feel the actors let their vines down.

Jonathan Groff (TV’s “Mindhunter”) plays Seymour, the hapless florist who, after an unexplained blackout, stumbles upon an unusual Venus flytrap-like plant that changes his life. His co-worker crush Audrey (Tammy Blanchard) starts paying attention to him, and Mushnik’s Flower Shop is bombarded by customers who want to see the strange creature Seymour’s named Audrey II. Problem is, this picky vegetation doesn’t live on water or fertilizer — it needs human blood. There are only so many ways to acquire that … such as murder.

Those familiar with Rick Moranis’ neurotic Seymour from the film may be surprised by Groff’s more subdued take. He doesn’t play up eccentricity or geekiness: He’s just one of those sweet guys society ignores.

Blanchard, too, doesn’t go the cartoon route with Audrey. She is genuinely anguished by her Skid Row life and her dangerous relationship with Orin the dentist (Christian Borle). You don’t have to look hard in New York to find someone who can belt “Suddenly Seymour,” but you do to find one as real and gut-wrenching as Blanchard.

And, yes, Michael Mayer’s production — with its blood and death set to bouncy tunes — is still hilarious. Borle’s dentist leaves you gasping for breath when he inhales nitrous oxide for kicks. His erratic energy is that of Jack Nicholson in “The Shining.” And there are laughs to be had at how perfectly big Audrey II (voiced by Kingsley Leggs) is puppeteered as Leggs croons “Feed Me.”

Don’t feed the plant, but do see “Little Shop.”