The Wilton Tangler is non-lethal weapon designed to ensnare and subdue a target without causing permanent harm. Tanglers fire "bolts" with cores of sticky grey plastic which expand rapidly into a sheet-like shape in flight, wrapping itself around its target on contact. A person hit by an expanded tangler bolt will find themselves inextricably caught in a sticky mess that contracts around them and holds them tight. Movement quickly becomes impossible.
Presumably, the plastic must be dissolved to free someone who has been "tangled" in such a manner.