Hoppin' Jack

The Hoppin' Jack is a Hardmode pumpkin-like enemy that will only appear at night during the Halloween seasonal event, or in Graveyards any time of year. It attacks by hopping towards the player in a manner identical to most Slimes. The difference, however, is that the lower on health it is, the quicker it becomes.

Notably, despite using the Slime AI, it is not treated as a slime for most other purposes. Hoppin' Jack drops no Gel on death, will remain hostile to a player with Royal Gel equipped, and killing one is not necessary to earn the Gelatin World Tour or Slimer/King of Slimes  achievements.

Trivia

 * The name Hoppin' Jack is a reference to, a creature from British folklore.