probably jirachi

There is no such thing as the strongest pokemon in the world. If there was then it has to be all types, which we know that thats impossible. Every pokemon has a way to beat it, and it has its own weakness. Dragon type for example its weakness is ice, and a duel-type example is water/ground (swampert or wishcash) even though its water type the ground type trait cancels it to it being not effecting it at all. So what you do is use grass type it triples the effect.

it probably make it more stronger and kill it