A Muncher (misidentified as a "Black Piranha Plant" by Lunar Magic) is an object that hurts the player on contact with it in Super Mario World. Despite only appearing within a handful of levels in the original Super Mario World -- namely Donut Secret 2, Chocolate Island 1, and Mondo -- they are commonly used in Super Mario World hacks. However, placing floating or stacked Munchers within a hack can be grounds for instant removal of that hack from SMWCentral.
Munchers turn into gold coins when a silver P-Switch is pressed. Unlike with enemies, the effect of a silver P-Switch is not permanent on munchers. They can be safely walked over if the player is riding a Yoshi, though touching them from the sides will result in Yoshi/the player being hurt.
Munchers Map16 number in Lunar Magic is 12F. Due to their status as an object, the creator of a hack can place an unlimited amount of munchers in a level. They can be Y-flipped to be placed upside-down, but ExGFX and ExAnimation must be used in order to make sideways Munchers.