Like the other Bombs, this card will kill itself at the start of your next turn to give you something. In this case, it causes its Dust effect to trigger twice instead of once. And that Dust effect makes you draw a card, with the drawn card getting its cost reduced by 2.
This can work well as a way to slow the enemy down, as if they leave it alone, you draw 2 cards and have a 1G profit. So if they don't want that to happen, they need to waste cards to silence and/or kill it before that can happen.