From Brotato Wiki
Item
Weird Ghost is an in-game item that can be bought from a Shop or can be found in a Crate. Most Items modify the Stats of the player, and some of them provide additional effects.
Weird Ghost
Weird Ghost provides Max HP at a discounted rate, but you start the next wave with just 1 hp. It is a gamble. Be careful with taking Weird Ghost if you are playing Sick or have the item Blood Donation or Bloody Hand.