What does the second verb show in دَحْرَجْتُهُ فَتَدَحْرَجَ?

Final Characteristics of Derived Forms: Ifʿīlāl, Ifʿilāl, Faʿlala, Tafaʿlala, and Related Patterns

• The result of the first action
• The color of an object
• Negation of the first verb
• A verbal noun in the accusative