Depending on where you time-travel in any stage, it is possible to get stuck in a wall. In Palmtree Panic Past or Future, teleporting to the present, in a wall near a ramp, will cause you to have strange running animations. Sonic always runs with his "going up a ramp" sprite, which is pretty funny because it happens even if you barely move!
As most of us know, if you were to wait 3 minutes, Sonic would say "I'm outta here!" and jump off the screen, resulting in an instant game over. However, if you were to wait above a pipe, or other objects that take away control from the player (you), you can show sonic that there's much more to live for, and he is saved. Or you could've just pressed start, you monster.