Malgyorg

Malgyorg is a shark-like sand enemy in Spirit Tracks encountered in the Sand Realm, however, most frequently seen in the immediate area surrounding the Sand Sanctuary. This foe swims through the sand, often in groups of three, honing in and attempting to heave itself upon the train. Though they may seem intimidating at first, Malgyorgs can be simply defeated with one carefully aimed shot from the Cannon. Because they only appear while Link is roaming the overworld on the Spirit Tracks, the Cannon is the only weapon capable of defeating them.

Blowing the train's whistle expedites the Malgyorg's jump, making it easier to target and defeat the foe, without the element of surprise in respect to the Malgyorg's ambush-like nature.