There are several types of anomaly that you can encounter. Some will chase you, others will infect you and some will just damage your armor and health.
Electric Anomaly[]
Has both static and moving versions. On contact it will destroy your clothes and armor, and will slowly drain your life. It can also follow you for a while. Spawns underneath pylons.
Fire Anomaly[]
Has both static and moving versions. On contact, it will steadily burn away your health and will sometimes follow you for a while. Spawns on rubble in the ruins or anywhere at night.
If you stay up all night in one place, away from a Hut, one of these will usually spawn near you. It often brings packs of Wolves, which you can harvest for Leather, Burning Zombies or just Shufflers. Make a note of its exact location - when it disappears before dawn it will leave a pile of Crystals behind - up to 7 depending on how long you stay up.
Water Anomaly[]
If you get close, this will pull you in and suck the air out of your lungs, slowly draining your health. Spawns underwater in fixed places.
Black Drops Anomaly[]
This is static (won't chase you) and on contact will infect you with a neurological disease, which will slowly drain your health. Damage increases as the disease bar fills up; once it's full, it will start dealing more damage. Spawns on beaches and in forests. Very rarely on Tesla towers as well.
Healing Anomaly[]
This will slowly restore your health. In critical situations (e.g., with bleeding, debuff, etc.), it can save your life or prolong it. Spawns at the mysterious shrine.
Dark Mirror Anomaly[]
Moves around randomly. If you get too close, it will pull you in and keep you trapped, applying high damage over time that can kill you quickly. Sometimes it will destroy all your armour and radiation suit equipped. Spawns on paths, in military bases or near beaches.
Common, lethal and very irritating. Very hard to see at night.
Teleportation Anomaly[]
On contact, it will teleport you to an unknown place. Some Teleportation Anomalies can also give radiation sickness, although this is uncommon. An easy one to find is on the beach near the transit point. If you follow the coast left on the bottom island, this anomaly sometimes spawns within the stone ring. Spawns on beaches or randomly at night.
If you use the Stone Circle Hut on the first island, you will know this is a permanent feature and takes you directly to the top of the highest mountain whenever you want! You can also see a pile of Crystals under the centre of the anomaly, and if you can find the 'entrance', you can actually get to them and collect.
Trapping Mist Anomaly[]
Will pull you in if you get too close, and will drain your health. Be sure to give these plenty of space. Spawns very rarely on Tesla towers or randomly at night.
Spawner Anomaly[]
This Anomaly is seen in the night time and can somehow spawn burning type zombies. They aren't common but not rare ether. They won't do anything to you or to the zombies but just spawn at least 2 every minute. It's best to avoid them as you don't want to get caught up by the zombies. They can be easily found on the battleship beach of doom or in the valley of black cloud.