Can a battery get overcharged/how to prevent it?

When charging a battery with a charger or using no charger and putting one battery on another battery can the low battery or both batteries get overcharged in some way?

What will happen to the batteries in the experiment and how can you prevent it.

I think I’ll try the battery to battery method first but after my last experiment where car was overheating don’t know if I should do any more experimenting.

Really broke at the moment hence these measures but hope I don’t have to go out and buy two more batteries.

Thanks