It is theorized that when the surface velocity is below certain minimum values the material at the interface between workpieces WP-1 and WP-2 rolls up and extrudes from the interface in the form of long twisted cylindrical projections which are sometimes referred to as "dingle-berries."
Source: wiktionary
Fire salamanders, which are common on forested hillsides in southern and central Europe, extrude secretions onto their skin containing a neurotoxic alkaloid, Samandarin, when they think they are under attack.
Source: wiktionary
When a printer is extruding and has open spaces in a layer, printers pull the filament back so that stringing does not occur.
Source: wiktionary
Researchers at the University of Warwick have created conductive polycaprolactone (PCL)-based filament by mixing carbon black into melted plastic before it's extruded as filament; they call the result carbomorph.
Source: wiktionary