I know that the Allies achieved quite a few success in terms of deceiving the Axis forces opposite them at Normandy, mainly convincing them the main attack would come at Calais with a completely fictious field Army under Patton. But I am sure not all the deceptions were equally successful, and one I am particular curious about is Paradummies? I don't have a lot of background on them, for example how long they made noise for, how many were dropped, or how effective they were in delaying the Germans. Were there accounts of German squads exchanging fire, or giving up their positions, or regrouping and closing in on these dummies? Or was the deception effective in other ways?
There were only 300 dropped, 200 south of Carentan, 50 more east of the River Dives and a further 50 south west of Caen. They had a device to make them explode and catch fire on landing. The Germans called them "Explosivpuppen". They were just a part of a larger scale action called Operation Titanic which also involved the dropping of aluminium strips (code name Window) to confuse radar and parachuting in small groups of British SAS troops to basically cause mayhem and chaos then disappear into the night. The total purpose of the operation was to create confusion and divert attention from the main landings. What they actually succeeded in doing was to convince most of the German Commanders that the whole invasion was just a diversionary tactic to keep them away from what they thought was the true invasion site of Pas de Calais. In doing so they stopped the Germans from releasing some of their larger Panzer and Infantry Battalions until much later. Source is D-Day by Antony Beevor which is well worth reading for anyone interested in the Normandy Invasion.