From the Super Mario Wiki
Dancing Spear Guys are a sub-species of Shy Guys that first appeared in Super Mario World 2: Yoshi's Island and are a variant of the Spear Guy (itself a Shy Guy variety). They dance to move, forcing Yoshi to evade their spears. Due to their movement pattern and the size of their spears, it is tough for the dinosaur to jump over them. They are edible, however, so Yoshi can simply swallow them. They are smaller than normal Spear Guys, without counting the spear. They also lack the shield and the feather held by a Spear Guy, and are a shade of yellow instead of red. The spear of the Dancing Spear Guy is taller than the spear of the normal Spear Guy.
Differences between Spear Guys
and Dancing Spear Guys.
They reappear in Yoshi's Island DS. They now have a greener shade on their masks (every other Shy Guy appearing in Super Mario World 2: Yoshi's Island had their palette changed to blue) and they move differently. They hop when moving, and after every hop, they make a circle and jump in height, then they hop again to move. They also grow in size. However, they are still smaller than regular Spear Guys, have a slightly longer spear than a Spear Guy and lack the feather and shield.
The idea was simple but effective in other Mario games. Chuck Guys from Mario & Luigi: Superstar Saga do the same, but instead of being harder to avoid, they make a call to others. They are not to be confused with another dancing maniac Shy Guy, the Limbo Guy, who made his appearance in Yoshi's Story.
Dancing Spear Guys made a surprise appearance in a Mario Party 4; however, they were holding torches.
In Mario Party Advance a Dancing Spear Guy named Hulu appears. She runs a dancing school in Shroom City and teaches the player to dance.
Names in other languages
||"Kanibalo" is derived from Kannibale (cannibal)