Disruptive Stormbrood // Petty Revenge

If the target creature’s power becomes greater than 3 before Petty Revenge resolves, the target is illegal and the spell is put into its owner’s graveyard.

If an Omen spell is copied, that copy is also an Omen and is shuffled into its owner’s library as it resolves. Its owner still shuffles their library, but the copy ceases to exist as a state-based action.

If an effect instructs you to choose a card name, you may choose the alternative Omen name. Consider only the alternative characteristics to determine whether that is an appropriate name to choose.

If an Omen spell has one or more targets and all of those targets are illegal when the spell tries to resolve, it won’t resolve. None of its effects will happen, and it will be put into its owner’s graveyard. It won’t be shuffled into its owner’s library.

Casting a card as an Omen isn’t casting it for an alternative cost. Effects that allow you to cast a spell for an alternative cost or without paying its mana cost may allow you to apply those to the Omen.

An omen card is a creature card in every zone except the stack, as well as while on the stack if not cast as an Omen. Ignore its alternative characteristics in those cases. For example, while it’s in your graveyard, Twinmaw Stormbrood is a white creature card whose mana value is 6. It can’t be the target of the reflexive ability created by Kishla Trawlers’s triggered ability (“…When you do, return target instant or sorcery card from your graveyard to your hand.”).