The Megatron statue is a massive piece of statuary in the form of Decepticon leader Megatron, located somewhere on the surface of the Transformers' home planet Cybertron. It is several hundred, if not a thousand feet tall; a normal-sized Transformer standing upright on its collar would barely come up to the statue's nose.
The details of the statue's construction are uncertain. From outward appearances, it seems to be carved out of stone, a material not normally found in abundance on Cybertron.
The statue appears to be sculpted in the form Megatron took after first landing on Earth rather than his original Cybertronian body. This was presumably an animation error given the relatively brief period Megatron was on Earth, unless he forced the entire Decepticon army to work on it while he was away or something.
After making his decision, Starscream flew upwards, past the statue's face.
Whether the statue survived Unicron's attack on Cybertron or the subsequent acts of carnage later visited upon the planet is unknown.