From Archon Arcana - The KeyForge Wiki
Ransack • Shadows • Action • Uncommon • Play: Steal 1. Discard the top card of your deck. If that card is a Shadows card, trigger this effect again. • Artist: Monztre • Card Number: MM:272, DT:221
With the exception of draw, if an ability references the top card of the deck and the deck is empty, the discard pile is not shuffled to form a new deck.
Source: Crucible Cast 4