Mechanical fist

Genkottsu is a trap which Mario faces in Super Mario Land 2: 6 Golden Coins. If Mario steps on the wrong floor panel in the Mario's castle level, a giant gloved fist in the resemblance of Wario's glove will come crashing down, pounding the floor with spiked knuckles at immense speed (although it is slower on Easy Mode). Mario will have to get past three of these traps in total in order reach Wario and rid him from Mario's castle.

Trivia

 * If Mario jumps over the center floor panels in the areas with these enemies, the trap will never be triggered and he can walk on by. He must jump over the center floor panel three consecutive times in order to avoid confrontation with all three of these fists outright.