>>12019664First time they're covered in Raichurubber (top grade stuff used for everything rubber in Pokeworld, big business) which absorbs all the shocks and hits.
But Pikachu fights hard.
So hard in fact
That all the Raichurubber is melted by the electricity and the build up of heat.
Now Raichus take a long time to regrow their Raichurubber, since it can take them up to a year if they're a bit older.
As a consequence, Raichurubber farms have to maintain hundreds of Raichus in order to provide a constant supply to the high demand (this is why there are so few "wild" Raichu left, think Miltanks and Moomoo milk).
Pikachu usually fights the Raichu within a week or two of the initial battle right?
The Raichu hasn't had long enough to regrow this "Rubber Armour" and so what we are seeing is a fight between Pikachu and a "naked" Raichu.
This is why Pikachu wins the SECOND time.
