It is an epentetic version of "descangallar" ("descoyuntar, spoil"), surely influenced by Galician or Portuguese escangalhar. See rested.
In some regions of Spain, it means to disrupt, destroy, spoil, damage, decompose, disarm. Break , fractionate .
ESCANGALLAR of Galician and Portuguese descangalhar . in Zamora, Spain: undo, uncoyuntar, desmadejar, destroy, break or spoil, in general a piece of furniture or an artifact, rest. In Asturian the spelling is DESCANGAYAR