Magikarp isn't the weakest Pokemon in the world. Here's proof: http://www.youtube.com/watch?v=ye7b3bOQ6lY
And I disagree about Sentret. Sentret was my most reliable Pokemon in Gold. :/
There are some Magikarp non-hacked SWEEP videos on Youtube. Just need the right Baton Pass.
Magikarp is NOT weak, he can do alot of stuff with baton passed max attack & speed and his flail (With 1-hit point)