Voidmage Husher is a 2/2 Wizard for 3U with a very powerful ability. The Husher has Flash, giving him (or her as in the case of the Time Spiral printing) the ability to be played at instant speed. When the Husher enters, you get to counter a target activated ability.
Activated abilities contain a colon. They're generally written "[Cost]: [Effect]." Some keywords are activated abilities and will have colons in their reminder texts.
In Commander, there are about a billion activated abilities that are worth stopping. Paying 4 mana to stop it is perfectly good. Plus, whenever you cast a spell, you can return the Husher to your hand.
Voidmage Husher sees play in a wide variety of Commander decks, including, but not limited to: Animar, Soul of Elements, Azami, Lady of Scrolls, Ephara, God of the Polis, Momir Vig, Simic Visionary, Nin, the Pain Artist, Oona, Queen of the Fae, Talrand, Sky Summoner, Teferi, Mage of Zhalfir, and others. The sheer number of opportunities to use the Husher’s ability makes it worth including in many Blue decks in the Commander format.
If you happen to find this comic laying around, it’s not a bad deal just for the card, and even better if you like the comics, too.