Untethered miniature robots, which can be used in applications ranging from cargo delivery to biopsy, demonstrate stunning performance in gastrointestinal (GI) tract treatment. The environmental terrains within the GI tract are complex and challenging for robots of limited size to pass through, where tissue mucus and winding surfaces tend to hinder robot movement. Herein, we report a multifunctional magnetic miniature truck robot (MMTR) that generates sufficient propulsion force to resist external environmental interactions. Its mechanical structure is optimized for integrating multiple functions, including climbing over obstacles, controlled drug dispersion, and cargo release. Using a programmed external magnetic field, the MMTR accomplishes transport of smaller-sized miniature robots by carrying them, allowing traversal of tortuous, branching, and restricted environments through adaptive morphology transformations. The introduced truck-unloading approach enables the MMTR to unload, detach, and retrieve sub-robots, demonstrating the significant potential of miniature robots for targeted transport.