Sore Loser

Sore Losers are one of three curse related enemies.

Behavior

Follows the player around and annoys them by getting in the way and projecting a spectral image in front of them, but cannot inflict any damage. When slain, the player's curse counter increases by 3.

Strategy

Sore Losers are not threatening on their own, because they can't attack. However, they can be extremely dangerous if they appear in company of many other threats, as there's no guarantee if the player would be able to lift the curse if they kill it during the crossfire.
Because of its extreme tenacity, one way of dealing with it is to simply lure it away from other mobs then kill it.
Other than to get enough kills for a kill door or to get the blueprints this enemy drops, there is no real reason to kill it, as it cannot deal any damage to the player.
If all of the blueprints haven't been acquired yet the Hunters Grenade can be used to polymorph Sore Loser into a standard Zombie elite, killing it after the transformation prevents the curse from being applied.

Notes

Player's pets and biters don't attack Sore Loser.
If this enemy dies because of environmental hazards, Crow's Foot caltrops, Electrodynamics’ orbs or direct damage from some grenades ( Oil Grenade, Infantry Grenade, Powerful Grenade, Cluster Grenade, Stun Grenade, Ice Grenade, or killing the elite spawned by using Hunters Grenade) the player won't get cursed. However, killing it with Turrets or status effects would still curse the player normally.