The Excavation Machines are machines in Professor Layton and the Last Specter.
Kidnapping Doland Noble, hiding him in Triton Manor's basement, Descole took his place so he could manipulate Clark. Through this, and also kidnapping Clark's wife, he could search for the Golden Garden far more easily.
Whilst disguised as Doland, Descole would pass on the location of the "specter's" next attack (which he already knew) from Luke to the police, so they could evacuate the area. This way, nobody would see the specter for what it truly was; specially designed excavation machines. Loosha would fight with the machines destroying the town. As their battles were shrouded with thick artificial fog (created from the water in the canals, which was Toppy's way of knowing which area was to be attacked, as the water level dropped), anyone who saw them would see a huge creature with glowing red eyes.
The machines were being built by the retired chief engineer at the old factory in secret. The thugs Descole and Jakes hired were made to guard the factory when Professor Layton realised what was happening there.He, Luke and Emmy managed to reach the heart of the factory, where several machines were ready. For Layton's explanation to the townspeople at Highyard Hill, Luke demonstrated one to prove Layton's theory.