How do they reproduce

After a boy electrode and a female electrode love each other very much they sleep together cuddling and during midnight, a secret agent from Silphco creates a brand new voltorb and shove it in an egg and places it next to them without being noticed.

the existence of hisuian voltorb/electrode implies that they are highly derived plant creatures, the pokemon legends arceus website even states that voltorb is full of seeds

perhaps exploding (and thus dispersing seeds) is hisuian electrode's way of reproducing, and this develops in the contemporary pokemon world with the ash being left over from the explosion being tiny airborne seeds that disperse

I thought Voltorbs came from Pokéballs containing dead Pokémon. As a Pokémon dies inside, it's body disintegrated into raw energy carrying it's soul; and this soul energy siphoned into Pokéball, "awaken" it into a new Voltorb.

They breed with wild Dittos. This is possible, because both live in Cerulean Cave. Ditto can lay Voltorb eggs.

Eggs are spontaneously created by Mew and delivered by Celebi

Fearow delivers their Eggs from Mt Coronet

Unrelated but I think Voltorb should evolve the same way Inkay does

Reminder that Pokemon "eggs" aren't really eggs. They are cradles.

a wizard did it

so when electrode explode they are cuming in public
Great
By the way electrode needs his own unique explosion move

seconding

Hisuian Electrode got one.

Really? Thats cool.