Ampharos is a yellow, bipedal ovinePokémon with a white belly. It has conical ears with black stripes and a red orb on its forehead. Its long neck has several black rings around it near the base. Its stubby arms resemble flippers and each foot has a single white nail. It has a long, black-striped tail with a red orb at the tip. The orb on its tail can shine so bright, that it can be seen from space. People have used the light as a beacon, or to send signals across the ocean. Ampharos is generally found in grasslands, though it can also be found in farms alongside its pre-evolved forms Mareep and Flaaffy.
As Mega Ampharos, its toes turn black and it regrows white wool at the back of its head and over its tail, having its genes stimulated by Mega Evolution. This energy also awakens its long-sleeping dragon blood. Its long wooly tail has many small, red orbs attached to it. Its conical ears retain their stripes but are now segmented with swirled tips. When it increases the amount of electrical energy within itself, the red orbs on its body and wool emit a strong light.
Ampharos, the Light Pokémon and the final evolved form of Mareep. Because Ampharos's light can be seen from a great distance, people once used that light to communicate by sending signals back and forth.
An early design for Ampharos depicts it with a shorter neck.
Ampharos shares the same category with Lanturn. They are both known as the Light Pokémon.
Ampharos resembles a sheared sheep that its evolutionary family leads up to as they lose wool with each evolution. It also shares traits with a lighthouse, such as its height, stripes, and the beacon on the top; the two also share a name. It, as well as its pre-evolved forms, may have been based on the title of the sci-fi novel Do Androids Dream of Electric Sheep?.
Mega Ampharos's Dragon type, wooly mane, wooly tail, jewel-like orbs on its tail, and slender body suggest that it is based on a Chinese dragon.
Ampharos may be a combination of amp (a measure of electrical current) and Φάρος pháros (Greek for lighthouse), as well as amparo (Portuguese and Spanish for aid and protection).
Denryu may be derived from 電流 denryū (electric current), as well as forming a pun on 電竜 den ryū (electric dragon). It may also incorporate 電球 denkyū (light bulb), referring to its tail.