for those who don't know, in sonic 1's usa cartridge, you can find the remains of what is presumably a testing room for the background decorations (trees, totems, etc), containing bugged graphics such as this red tree. to get to it, you need to activate debug mode and go to marble zone act 3. on the 3rd vertically-moving platform in the stage, spawn a box of speed shoes and use them. then, wait until the platform is going upwards, and run at the wall with as much momentum as you can. if done correctly, you should get stuck in the wall doing the pushing animation. from here, all you need to do is try to walk to the right, and it should clip you to the bottom of the stage. if everything has been done correctly, an unused and bugged version of the motocheck failsafe will trigger, sending you to this test room. not real :(
everything in this project belongs to sega and sonic team