Mace Guy

Mace Guys are rare enemies within the Yoshi's Island series. They appear as a rare variant of a Shy Guy, wielding and swinging a Ball 'N' Chain so as to damage Yoshi. However, Yoshi is able to eat the Shy Guy, spitting it out to turn it into a regular Shy Guy. This may also happen if one is frozen with an ice watermelon. Despite their name, the weapon they wield is in fact a flail rather than a mace. Additionally, while the artwork depicts the flail as black with white spikes, the sprite depicts it as light blue with yellow spikes.

Mace Guys first appear in Super Mario World 2: Yoshi's Island, where they appear in only three levels: Sluggy The Unshaven's Fort, Raphael The Raven's Castle, and Ultimate Castle Challenge. They return for one secret level in Yoshi's Island: Super Mario Advance 3: Endless World of Yoshis. They reappear once more in Yoshi's New Island.

Yoshi Topsy-Turvy features Mace Guys in a total of seven missions. All but one are in the sixth chapter, and a lone one is found in the fifth chapter.

A Mace Guy also appears as a sticker in Super Smash Bros. Brawl. The sticker increases the strength of a fighter's weapon by twenty-two points.

Shy Guy appears as a Mace Guy during its Special Shot Spin Strike in Mario Golf: Super Rush. Its flail is black with white spikes for the first time since Yoshi's Topsy Turvy, but with a more proper handle. The game also marks the debut of blue, yellow, and green Mace Guys, which are seen after unlocking the Shy Guys' alternate colors from Ranked Match on the last day in February and the month of March. Pink, Cyan, and Orange Mace Guys also debut after unlocking Shy Guy’s alternate colors from the Ranked Match in August.

Super Mario World 2: Yoshi's Island

 * Player's Guide: This swingin' guy invites dinos to dance. Yoshi shouldn't swallow the bait, but the Mace Guy himself.

Yoshi Topsy-Turvy

 * Shogakukan guide: 鎖のついた鉄球を振り回すヘイホー. 倒し方は通常のヘイホーと変わらない. また、鉄球を振り回すスピードは、コースによって異なる. (A Shy Guy wielding a chained iron ball. The method of defeating them is the same as that of regular Shy Guy. Additionally, the speed at which the ball is swung depends on the course.)