An Automatic Activity is an action that a BIC performs in a flow. When you place a new Automatic Activity on the canvas, you are prompted to choose a BIC, and then to set properties for the activity. Among the settings you can modify for an Automatic Activity are its work item priority, expiration period, and inbound and/or outbound properties.
For more information, see Using a BIC in a Flow.
Note: Automatic Activities can sometimes serve as starting points in a flow, depending on the BIC.