We report the case of an 87-year-old female who died after coil embolization of an intracerebral giant aneurysm. Guglielmi detachable (Boston Scientific Neurovascular, Fremont, CA) and Matrix2 coils (Boston Scientific Neurovascular, Fremont, CA) were used during the procedure to occlude the surgically untreatable left supraclinoid carotid artery aneurysm. Postprocedure imaging studies showed scattered areas of acute infarct involving multiple bilateral vascular territories. Autopsy confirmed widespread infarction due to embolized foreign material, morphologically consistent with hydrophilic polymer originating from the coated Matrix coil and Terumo glidewire (Terumo Medical, Somerset, NJ). Polymer gel is now widely used on several medical devices for interventional procedures worldwide, and we suspect that risks associated with iatrogenic embolization of this substance are underrecognized.