A standard anomaly creates an obstacle which the player can investigate, sometimes at their own peril, or go back a card to avoid.
These anomalies the player cannot avoid
These anomalies do not do any harm but add an air of mystery
These anomalies have effects that last multiple turns or create quests for players
Time anomalies will through the player into the future or past. This is why it is important to track players activities for they may need to replace events.