Using their very hot, flame-covered tongues, they burn through Durant’s steel bodies and consume their insides.
– Pokemon White Pokedex
Heatmor is ugly. It’s based on an ant eater, which eats Durants, according to the Pokedex entry (rather gruesomely it seems). Durant is Bug/Steel, which is only (doubly) weak to Fire, which is why Heatmor is Fire type I guess. Its also sort of based on a volcano or something, with its tail looking like a stovepipe. It’s found in Victory Road in Unova, which is shaped like an ant hill.
Stat-wise, it has good Sp Attack and decent Attack, but its other stats are subpar. There are other much better Fire types out there. Heatmor seems a bit like a filler Pokemon to me, perhaps created as a counterpart to Durant.