S.T.A.L.K.E.R.: Shadow of Chernobyl
"Artifacts" are the product of 'anomalies', which occur randomly throughout the game. Anomalies are normally a few metres across, these areas are dangerous to enter and can instantly kill the player or cause serious injury. They can be seen by looking for swirling leaves, heat waves, wind moving about, and electricity. An anomaly will be in the game for about one week in game time, and once they have disappeared the player is able to collect the artifacts left behind, which can be traded for supplies, or worn to enhance some player abilities, with normally some bad side effects; for example, there is an artifact in the game that can make bullets less likely to hit the player, but will slowly give the player radiation sickness, which will eventually kill the character being played.