The vigil went down Wednesday night at the Oakland mural that just went up honoring the late "Euphoria" star.

Local artist Darin Balaban, who painted the 9-foot-tall mural on the wall of an Oakland car wash, tells TMZ ... around 50 people showed up to the mural for a candlelight vigil, with many bringing flowers and pictures of Angus and placing them at the base of the wall.

Others brought liquor and Guinness beer, and the group played music and sang songs together ... swapping stories and even adding to the Angus mural.

We're told some shed tears, but there were also a lot of smiles as people remembered the young actor.

Video from the vigil shows the group singing Ben E. King's famous song, "Stand By Me."

TMZ broke the story ... Darin and a group of Angus' friends collaborated on the mural, mashing up 3 photos of the late actor, and the artwork is already becoming a gathering place for those wanting to pay their respects.

As we first reported, Angus died Monday at his Oakland home, where his mom reported a possible overdose ... and he was pronounced dead at the scene.