Manectric in depth
A raijū with a crocodile clip
The starting point is a dog, but not only that. The design crosses canine anatomy with the raijū, the lightning beast from Japanese folklore, and the result breaks away from the canine canon in one very specific place: the snout. It ends in an angular, split point that calls to mind a crocodile clip used to attach to a terminal. That is what keeps the face from reading entirely as an animal's.
The Japanese name, ライボルト, stacks several things together: 雷 (rai, thunder), lion and volt. English goes straight for it, mane plus electric, the mane and the current, which is exactly what you see from a distance. Spanish left it untranslated, like almost all of the third generation.
What Mega Evolution brought
Mega Evolution appeared in Omega Ruby and Alpha Sapphire, with the mane swept backwards, much longer and bristling with new spikes running across its body. The reference there points to the maned wolf: tall legs, an elongated silhouette, the dark mane like a cape. The fundamental change is the ability, which becomes Intimidate, and the stat distribution, which pushes Special Attack and Speed upwards.
It is worth comparing the three abilities of the regular form, because they are a good example of how uneven a trio can be. Lightning Rod does something real in doubles. Static does something sometimes, if the opponent happens to use a contact move. Minus does nothing except on a team deliberately built around Plus and Minus, the sort of combination almost nobody runs.
The dog that arrives late
As an adventure partner, the order in which it learns its moves explains quite a lot. At level 1 it already has Thunder Wave and Fire Fang, which provides coverage against Grass, Ice and Steel from the first turn, although wasted on an Attack stat of 75. Shock Wave, at 16, stays at 60 power. Spark, at 36, rises to 80. Thunder, with its 110 power, does not arrive until 54, and Electric Terrain closes out the list at 60, a level by which most playthroughs have already ended. The gap between 36 and 54 is covered with TMs: Thunderbolt has 90 power and is obtained much earlier.
The unavoidable comparison is with Luxray, the other Electric dog in the series, which distributes its points the other way around and hits from the physical side, and with Jolteon, which occupies the same niche of fast special attacker with better numbers in its area. Manectric ends up in the middle, without either one's power or the other's Speed, but with the advantage of having a Mega Evolution that neither of them has.
What never changes in any generation is its fragility. Sixty points in each Defense stat, with 70 HP, makes for a body that takes one strong hit and no more. Everything it does has to happen on the turn it comes in.