Rocket's Secret Experiment
Challenge from the Darkness · #promo · Uncommon · 1998JPN
Price history
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Graded values
Grades 1–6 are estimates modeled from the raw price — PSA/CGC/BGS 7–10 and Ungraded are live tracked market values.
PSA 10 chart is building — graded values are tracked nightly, a new point appears each day.
Graded population census · updated 2026-09-18
Population data from PriceCharting, updated monthly.
How much is Rocket's Secret Experiment #promo worth?
A raw copy of Rocket's Secret Experiment #promo (Challenge from the Darkness, 1998) is worth about $3.97 right now, based on the latest market data from November 7, 2026.
Grading changes the math on this one: a PSA 10 is valued around $123.58, roughly 31.1x the raw price, while a PSA 9 sits near $19.00. 96 copies have been graded to date, and 24% of them came back a 10 — worth knowing before you pay grading fees.
These figures come from nightly market-data syncs verified against completed sales. Use the chart above to see the trend before you buy or sell.
