Mega heatmor dwells in mountainous areas trying to infuse lots of other chemicals in its flames. It does this so its six tongues can pierce through mega durant's normally heat resistant armor.
Mega evolution melts durant's old metal and causes a new set of heat resistant armor to form. This new metal serves well to defend itself against heatmor, but mega durant's heavily increased speed helps it run away from the much more dangerous mega heatmor.
by Every_Confection4265