They kind of look a bit like fish without that beak.

In some birds like ducks, the serrated teeth structure in the bill is pretty visible (mud ducks often use it to filter water from, well, mud).

Gooses can even use them to deliver powerful, painful vice grips to drive off intruders (some people use certain species, like the chinese goose, as "guard dogs". Try to jump in thinking they're just big birds, I'll wait).

(Below, an ordinary goose and the chinese goose, the one who's just one mega stone away from becoming a cassowary)

we're gonna rek u m8