Bob-ombs are living, moving mechanical bombs with eyes, feet, and a wind-up key on the back. They are 𝐮𝐧𝐢𝐪𝐮𝐞 enemies who first appeared in 𝐁𝐨𝐛-𝐎𝐦𝐛 𝐁𝐫𝐨𝐬, and have appeared in nearly every 𝐁𝐨𝐛-𝐎𝐦𝐛 game since then. Their appearance, intelligence, and status in relation to Mario differ widely from game to game. They are usually either blue or black, but some variations are pink or red. They also flash red and sometimes make beeping sounds if they are about to explode.