Board Thread:Questions and Answers/@comment-24812000-20170301003315/@comment-4651179-20170301012916

That plot point is expanded upon in. In a flashback we learn that in college, Ben accidentally bumped with Victor while he was carrying ultraviolet paint, causing Victor to lash out at him and insult him.

Because of this, Ben then decides to sneak into Victor's lab together with two of his friends and mess with his machines. However, the scene makes heavy focus on Ben partially rubbing off one of many magic symbol that Doom had painted with the ultraviolet paint on the walls and ceiling.