After Obito Summoned the Gedo Mazo (The Juubi's husk) in the 4th Great ninja war, he tried to retrieve the gold and silver brothers but was stopped by Darui and shikamaru. (Shippuden 276). In order to get the brothers, Obito controlled the Gedo Mazo to step on shikamaru.
How was this possible? it seemed more like he neither needed to say anything nor give it orders to control it, like it reacted to his thoughts, and it got me wondering if the Gedo Mazo is the only exception to summoning rule where the user can directly control his summon? If that weren't the case then what actually went down.
Could this be related to the power of the Rinnengan?