Noko Bombette

A Noko Bombette is a Bombshell Koopa whose shell has grown so much it evolved into a Buzzy Beetle in Super Mario Land 2: 6 Golden Coins. Unlike regular Buzzy Beetles, Noko Bombettes turn around when they reach a ledge, but they are still immune to fireballs. Unless a Spin Jump is used, jumping on a Noko Bombette will cause it to explode after a few seconds. If Mario is caught in the blast, he will take damage.

Super Mario Land 2: 6 Golden Coins

 * Virtual Console manual: "This is a turtle with a bomb on its back. Beware! This armed reptile explodes when you tread on it."