Appearance and Behavior
The Lost Soul appears as a skull with a viking-like helmet with four horns total and small red lights in their eyeballs.
It floats in the room heading straight towards you while slowly gaining more height until reaching a certain maximum. When flying over stairs they either lose height slightly or gain it a lot faster depending on if they fly up or down on them.
Attacks
Lost Souls use a sort of charge attack against the player. When they are close enough they drop straight down until they reach your height, when they will rush towards you with rather high speed in a straight line, dealing contact damage if they fly through you. They can't collide with you.
Hints
Lost Souls spawn in even larger numbers than all the other minor minions, but have even less health, so be prepared for an army if you spot one.
Their hitboxes are rather small, making it hard to hit them. Shots clip trough their horns, only the skull itself takes damage.
Their attack goes in a straight line, so they are easy to dodge by simply staying mobile, unless you run straight into another one of them.
Choose a weapon with great accuracy or something with a shotgun-like effect in order to kill them quickly.