do you mean like a one-way wall?
hmmm, you might be able to place an actor in that spot, but set it to spawn later, then place a trigger in that spot with an 'on exit' script that spawns the actor? i wonder if i can make an actor type that's basically a "wall" that lets you go through it X amounts of time before it becomes solid... that might be handy for puzzle games, i think!
https://liftedpixelgames.itch.io/pxgba/devlog/1578655/034
added a "pass wall" actor type - you can set it to be solid after X frames, after X frames after being pass through, or after X amount of passes. set the idle animation to the state you want it to look like when the user can pass through it, and set the walk (or any other) animation state for when it's solid, then set the animation in the actor config :)