I suggest you join the Discord. We post videos about setups and how to do them. Also, it is called the Scroll Glitch

It’s a bit of a complex glitch so i’m going to copy paste the explanation I wrote for the Castlevania wiki here:

“This glitch is related to Castlevania's way of loading tilesets offscreen. Blocks may only be loaded every 2 frames, and only while Simon is moving. This means that by moving only on frames when blocks are not being updated, they will fail to load properly and instead leave on screen a predetermined, consistent "garbage" tileset. Attempts to load the blocks will continue until Simon is close enough to them. Usually this requires the user to perform 20+ 1-frame movements on the correct frames, which is unfeasible in a Real Time setting. There is another exploit to this mechanic though: if, on the frame a tileset would normally load, Simon moves BACK instead of forward, the block will fail to load, and no further attempts will be made to load it until 8 more frames of movement on "loading frames", at which point another turnaround will be needed. Usually two or three turnarounds are needed to permanently prevent a tileset from being loaded. This method is feasible in Real Time and leads to a number of skips.”

As far as my setups go, I explain the one I use for stage 14 here: And I explain the one I use for stage 13 here: