Shadow Spider

It appears to be an animate shadow of an unknown species of spiders. It avoids illuminated areas, and
usually wanders in dark places. If a player attacks a shadow spider, the spider will try to approach and bite the player.
If successful, the player will receive an unknown malign condition with 4 stages. All shadow spiders will avoid the
player with this condition from then.
Second stage manifests after 3 minutes from the bite - the player gains strength, slowness and aggression effects.
Aggression makes player to hit things randomly.
On third stage player gains weakness and fatigue. He will also experience nausea when located in illuminated areas.
On fourth stage player dies, with an unknown type of liquid pouring out of his corpse, and few shadow spiders spawning
 from it.
