Hush is a spell, cast only by the hush puppy (it is impossible for the player to learn it), which causes the player to lose the ability to cast magic for the rest of the game.
Consuming the Mama Mia Pasta Sauce made by the Sicilian She-Dwarf will reverse the effect (as it reverses all effects), but since the sauce can only be consumed once, this is of no help if the spell is cast again or if the player has used the sauce as a bribe for the Gnome Crimelord. (Because it is a spell and not a curse, Hush is not removed when you mate.)
Players who have been transmogged to charcoal can still cast Horrible Burning; crystal dwarfs can still cast all their spells, making them immune to the effect. Of course, because the player needs to cast a spell in order to bounce a transmog off a glass creature in the first place, this is only a precautionary measure and not a way to reverse the spell.
Eating the flesh corpse of the exact same hush puppy that has cast the spell-- not killing them, but letting proximity to a charcoal creature cook them-- will undo the effect.