Warden Helmet

 is a helmet which halves your speed but gain  more base damage for every   you have.

Trivia

 * Because of its base weapon damage boost, a Giant's Sword is a great option to pair with this, due to it having the highest base damage out of all weapons.
 * Having a Black Cat Pet or Rancher's Boots helps increase speed a lot for this item's ability.
 * It's ability is maxed out at 200, but goes to 250 with a Level 100 Black Cat.
 * The Warden Helmet (and its ability) may be a reference to the Warden of Alcatraz prison, Brutus; a boss from Call of Duty: Black ops II Zombies map "Mob of the Dead", also appearing in Call of Duty: Black ops 4 Zombies map "Blood of the Dead".