Pose!
A Master Sentinel is an enormous version of the regular Drakon Sentinels, but only one is known to have existed. It rose from the sea next to the Emerald Hill Zone, where its orders were to march towards the village and destroy the Emerald Hill folk if Sonic the Hedgehog did not surrender.
The Master Sentinel was furious at first when Sonic threw a stone at its head and caught Sonic in its fist. The Sentinel was then swallowed by the water thanks to Sonic's Water Vortex trick. The attack did not finish it off, but did expose a hole in its chest plate. Sonic, with the help of Tails, flew up to the hole, jumped inside and cleared out the robotics with some speed. With no power, the Drakon fell back on to the ground.