Springboards appear only in the Ice Caves.
They are randomly placed on the ground and can be seen as a raised bump. Stepping on a springboard will launch you into the air, roughly 5 to 6 tiles high. Normally, this wouldn't matter too much, but in Area 3 it does for several reasons. The first being: All of the levels in Area 3 are bottomless, meaning you will instantly die if you fall into the pit. Secondly, springboards tend to be generated on ledges, and unexpectedly being launched into the air is likely to cause Fall Damage unless you have a Parachute, Cape, or Jetpack to slow your descent. However, falling onto a springboard from a great height will negate any fall damage you would have received otherwise.
Yeti can also be launched by springboards, which can be both unexpected and deadly.