Nothing beats all those Fawful moments, especially the moment when...
...after knocking Bowser out, tries to do a sneak attack on the Mario Bros. by approaching behind them in order to "scare" them while they're checking if Bowser was okay.[/spolier]
Look for a gate (I think it's northeast of the Castle Town?) that requires you to use Fire or Thunder (I don't remember which) and follow that path, which will eventually lead you to a cave. The Hammerhead Bros. have moved into the cave, they will make you the hammers. The gate is in an area with an annoying Lakipea, i know that much.