Cause of vomiting of a black, fairly large (1-1.5 inch) solid "fuzzy" material, along with undigested food that was consumed 3+ days ago?

Not entirely sure: Not clear what this is, but it is quite unusual sounding and vomiting undigested food from 3+ days ago is not a good sign - b/c it means you have not processed any food in 3+ days. Concern would be an obstruction somewhere, but must be evaluated in conjunction with other sign/symptoms and findings on exam. Dehydration and electrolyte imbalance must also be evaluated and treated urgently if present.