Steelix

Steelix is a long, serpentine Pokémon with a silvery-gray body made up of rock-like sections, which can possess chips and scrapes from fights and tunneling. Three of those sections have long rock spikes coming out of them on either side. It has a massive head mainly made up of its large, wide jaw with sets of large square teeth inside. Along it bottom jaw are ridges: there are two pairs of ridges on a male Steelix, while there is only one pair on a female. Several small, square lumps cover the underside of its lower jaw. Its eye sockets are slightly deep set, and the eyes themselves are red. Its head has two long ridges going from the eyes up to the top of its head. The tip of its tail is conical with a blunt tip.

As Mega Steelix, its body becomes longer, almost doubles its mass, and gains more features. Mega Steelix's eyes turn blue and its lower jaw becomes more heavily armored with a round, curved shape. Additionally, a third pair of ridges appears on its bottom jaw, as well as two sharp, flat structures consisting of three conjoined projections on each side. The gray, rock-like spikes and its tail point have transformed into prism-like crystalline spikes; the segments from which the spikes protrude are much larger as well. In-between the head and individual spiked segments are smaller units, now adorned by a black spot with a blue hexagon on each side. Several metallic-looking scraps constantly rotate around its neck; these scraps react to Mega Steelix's movements and change position when attacking. The cells within its body, crystallized by the energy produced from Mega Evolution, are stronger than any mineral and able to withstand any temperature. It moves incredibly slowly, but its strengthened body is also impervious to damage, and it lashes out at foes without flinching. [1]

Steelix burrows up to six-tenths of a mile underground and can be found in mountains or caves. It easily chews through boulders with its powerful jaws, and its eyes are capable of seeing in the dark. Exposure to underground heat and pressures alongside its iron-rich soil diet have made its body harder than diamonds.