What is thunder weakness Pokemon?

Answer 1

Some peeps thinks its rock cause thunder does no effect to rock types

hmm.. pikachu, arceus thunder, jolteon and blah blah and all the other Pokemon they'll all weakness to fightin type even Pokemon cards says it too!! check in Google! the cards i mean yall show u picture

so ya sorry .. THUNDER TYPE IS WEAKNESS TO FIGHTING TYPE yhh i'd say FIGHTING TYPES :)