Pierre-Emerick Aubameyang pulled a Black Panther mask out of a bag behind the goal to celebrate his strike against Rennes.
It was the second time he attempted the celebration this week — he tried the same against Manchester United at the weekend but could not find the mask.
Black Panther is a Marvel superhero and was the main character in a film of the same name, released in 2018. It was nominated for seven Oscars.
Aubameyang also crossed his arms in celebration, performing the 'Wakanda Forever' gesture that is used as a greeting in the film.
The striker was famous for his masked celebrations at Borussia Dortmund, wearing Spider-Man and Batman masks after scoring, but Thursday was the first time he performed one in an Arsenal shirt.
Speaking about his attempted celebration against United, he said: 'I had a special celebration planned but I couldn't find my mask.
'I asked a member of the staff to put it in the back of the net but when I scored the penalty I couldn't find it.
'But no worries. Maybe next time.'
