Doctor Who
Object

Terminus' Unstable Fuel

The unstable fuel appears as a volatile, invisible substance ejected from Terminus' damaged engines into the void. Its instability manifests in catastrophic potential—the Doctor describes it as capable of igniting the Big Bang itself when ejected into the primordial void, while Kari recognizes its modern-day remnants could trigger a second universe-ending explosion from the ship's failing engine. The concept underpins Terminus' cosmic origins, tying its present location at the universe's center to an origin point of creation and destruction. Its violent expansion births time and space itself, with the shockwave of its creation still resonating through the universe’s fabric.
1 appearances

Appearances in the Narrative

When this object appears and how it's used

1 moments
S20E15 · Terminus Part 3
Doctor reveals Terminus cosmic origin

The unstable fuel serves as the pivotal plot device through which the Doctor and Kari deduce Terminus's cosmic origins and imminent doom. The Doctor frames it as having sparked the Big Bang when jettisoned into the void, while its modern-day remnants in the station's damaged engine now threaten a second explosion capable of destroying the universe.

Before: Present as an invisible, volatile substance whose only physical traces are the ship's damaged engine and Bor's deteriorating condition from exposure
After: No longer inert—the revised understanding of its destructive potential elevates it from a navigational hazard to an existential threat demanding immediate action
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