Clock Tower Prison

Clock Tower Prison was introduced in the 2006 Duelist Pack: Aster Phoenix set, designed to complement the specific archetype used by the character Aster Phoenix in the Yu-Gi-Oh! GX animated series. The card serves as a Field Spell that provides a unique defensive mechanic, requiring players to maintain the card on the field for four turns before its ultimate effect—which prevents all battle damage to the controller—can be activated.

The visual design of the card reflects the dark, industrial aesthetic characteristic of Aster Phoenix's Destiny HERO deck. By representing the passage of time through its clock counter mechanic, the illustration captures the strategic tension of the anime duel it originated from. While the card is often cited by players for its challenging activation conditions, it remains a notable piece of GX-era history for its creative approach to field control and its direct ties to one of the series' most iconic antagonists.