From WiKirby, your independent source of Kirby knowledge.
Pierce is a flying enemy from Kirby's Return to Dream Land. It is first encountered in the Onion Ocean level and grants the Spear Ability when swallowed.
Pierce resembles a large bumblebee with a spear in hand and a very big head and purple earmuffs. When spotting Kirby or his friends, it will charge slowly toward them and attempt to strike them with its spear. It is generally not tough to deal with.
Pierce also appears briefly in Kirby: Triple Deluxe, more or less unchanged, and still provides the Spear ability. It gains the ability to fly between the foreground and background in this game.