When players explore a dungeon, at certain locations on the map stuff is supposed to happen: Maybe they stepped on a trap, or they came into view of a group of monsters. What frequently happens to me on Roll20 is that the players move their tokens at a certain speed, and by the time I can tell them that something happens, they are already past the point, and I need to ask everybody to stop or even backtrack. Is there any way in Roll20 to stop player movement automatically at a map location? I know I can use "Dynamic Lighting Barriers Restrict Movement", but as these barriers also restrict view, they are very visible. I would need at least a "transparent" barrier option to stop the player from moving further without making the location too obvious. Does that exist? Or is there some other sort of trigger I could put on my map?