In Mario Bros., the Sidestepper is the crab enemy that needs two hits from below before it can be kicked away.
Mario Bros. does not let players simply jump on its enemies. Mario or Luigi must strike the platform beneath an enemy to flip it onto its back, then run into the stunned creature to kick it off the stage. A Shellcreeper usually flips after one hit, but the Sidestepper requires a second strike.
That first hit has an extra consequence: the Sidestepper becomes angry and moves faster, making the follow-up attack more dangerous. If the player waits too long after flipping it, the enemy can recover and return to movement. The POW block offers another way to turn enemies over, but careful positioning is still needed to kick them away.
Mario Bros. was released as an arcade game in 1983 and features four main enemy types: Shellcreepers, Sidesteppers, Fighter Flies, and Slipices. Its sewer setting, platform-bumping combat, and screen wraparound established mechanics that differ sharply from the later side-scrolling Super Mario Bros. games. The Sidestepper’s two-hit behavior is therefore a defining detail of the original arcade-style gameplay.