Giant serpentine aneurysms (GSAs) are a rare subgroup of intracranial aneurysms. Separate inflow and outflow flow due to intraluminal thrombosis is the most distinguishing feature of GSAs. In treating these lesions, surgical clipping and ligation were the main treatments in the past, but bypass for revascularisation and endovascular therapies (EVTs) for deconstructive purposes are more prominent today. A 51-years-old male patient presented with headache and mild right hemiparesis. He had a GSA arising from the left fetal type posterior cerebral artery (fPCA) that was out of follow-up for six years. Radiological images revealed midline shifting and mesencephalon compression. We performed endovascular parent artery coil occlusion. The symptoms of the patient improved at the first-month follow-up. Even if there is a mass effect in GSAs, deconstructive EVT is a safe and feasible method for managing these lesions.