In Super Mario World, whenever Mario passes over the bridge in the Donut Plains part of the overworld, a Cheep Cheep jumps out of the water below him. If the game is paused while Mario is on the bridge, the Cheep Cheep will continue jumping forever.
In Super Mario World, jumping on the platforms in Vanilla Ghost House in the order shown will produce a hidden 1-Up. The reason is that four of the platforms contain special control points that, if touched in order, will generate a 1-Up when Mario touches the last one.