Moneybag

Moneybags are little cute monsters that resemble coin purses with feet. Here is a list of games they appear in and their behavior.
Super Mario 64
They disguise themselves as coins until you get close to them, then they start to hop around. A Ground Pound will make it release 5 coins. Only appears in Snowman's Land.
New Super Mario Bros.
Same behavior, but now it takes 6 stomps to defeat. A coin will be released with each stomp. Otherwise, a single shell or Mega Mushroom will defeat it instantly. Appears in 2 levels.