How Many Packs to Pull Gyarados-GX from Crimson Invasion

Gyarados-GX chase methodology

This page answers exactly one question: how many Crimson Invasion booster packs does it take to pull Gyarados-GX #18? The numbers below come from the same per-rarity pull-rate model the PackRip Crimson Invasion simulator runs on, mirrored from packGenerator.ts. TCGplayer pricing refreshes every build, so the buy-vs-rip verdict at the bottom reflects current market.

The math: ~1 in 81 per pack

Gyarados-GX sits in the GX rare-slot pool for Crimson Invasion. There are 9 GX cards in the Crimson Invasion pool, and the GX slot fires with probability 11.10% per pack. Since the slot is split evenly across the 9 cards in that tier, the per-pack chance of pulling this specific card is 1 in 81 — approximately 1 in 81.

Pulls are independent and identically distributed, so the number of packs until you hit Gyarados-GX follows a geometric distribution with parameter p = 0.012333. The expected number of packs is 1/p — that's ~82 packs on average. But "average" hides huge variance: the median pull lands faster than the mean (~56 packs at 50% confidence), and a long unlucky tail can stretch the wait dramatically. The 95% confidence band — 242 packs — is where 95% of pull-runs finish; the remaining 5% take even longer.

Concretely: if 100 collectors each opened Crimson Invasion packs until they pulled Gyarados-GX, roughly 50 of them would have it by pack 56, 95 of them would have it by pack 242, and a handful would still be chasing past that. Expected ≠ guaranteed; the geometric distribution is famously long-tailed on the right side.

Confidence bands — packs vs cumulative probability

Read this table as "what fraction of openers have pulled Gyarados-GX by pack N?". A 25% band of 24 packs means a quarter of openers hit it inside that window; 99% means almost everyone has hit it by pack 372. The dollar column anchors the variance to real-world sealed-pack cost at $5/pack.

Cheaper to buy Gyarados-GX as a single?

Buying Gyarados-GX as a single on TCGplayer (~$25.80) is dramatically cheaper than chasing it through packs — the expected pack-rip cost is roughly $405, well above the market price.

Pack-rip expected dollar cost for this specific card: ~$405 at $5 per Crimson Invasion pack. Compare to $25.80 for the single on TCGplayer (Unlimited / non-graded copy at current market). The single buy obviously delivers exactly this card; the pack-rip approach delivers Gyarados-GX plus the remaining 10 cards in every pack along the way — which is why the EV calculator at /ev/sm4 spreads the cost across the whole pack contents instead of pinning it to one card.

About Gyarados-GX (Crimson Invasion)

Gyarados-GX is a GX card from Crimson Invasion, the 2017 Pokémon TCG expansion. Crimson Invasion (2017) introduces the Ultra Beast subtype to PackRip's catalog on 13 of its 126 cards. Nine cards carry rarity Rare Holo GX, including a Guzzlord-GX alternate at #63a. Its five Secret Rares are all Trainers and Energy. The set is compact by Sun & Moon standards and its type spread is unusually flat, led by Water at 17.

This specific card ranks as one of the top-3 most valuable pulls in Crimson Invasion by TCGplayer market value, which is part of why the chase math is what it is — high market value tends to track with rarity-tier depth, since lower pool sizes concentrate value into fewer cards. The complete top-25 Crimson Invasion ranking shows where Gyarados-GX sits relative to the rest of the chase pool.

Pull odds in context

For reference, a "1 in 81" pull is roughly comparable to a moderate chase — you should expect to crack a couple of boxes. The variance is the killer: any one pack could be the one. The simulation on PackRip's Crimson Invasion opener uses the same exact RNG model, so you can stress-test the wait curve without spending real money.

Related chases

• Lusamine — Full Art, $42.33 market
• Gengar — Rare Holo, $24.82 market
• All Gyarados-GX printings across 4 sets
• All top-25 Crimson Invasion chases
• Complete the Crimson Invasion binder — full calculator

Open Crimson Invasion free

Rip Crimson Invasion packs free on PackRip's simulator with the same per-rarity pull rates this page is built from. The Hunt Pack mode boosts the GX slot if you specifically want to optimise for Gyarados-GX-tier pulls. Coin economy is virtual — no real money on the line.

Strategy: optimising the Gyarados-GX chase

Every experienced Crimson Invasion hunter eventually picks one of three approaches for a specific chase card. The cheapest is the snipe: skip pack-ripping entirely, set a TCGplayer alert at or below the current $25.80 market, and wait for a motivated seller. This is the route most efficient-frontier collectors take when the chase is locked behind a deep rarity tier — and the math above shows why. The expected pack-rip cost ($405) is typically multiples of the single price, and the variance on that expectation is wide enough that a single bad streak can blow past the 95% confidence bound. The single buy is dollar-for-dollar cheaper and emotionally cheaper too — no more refreshing pack-pull videos at 3am.

The middle path is the box-rip-then-snipe: open a sealed booster box of Crimson Invasion (typically 36 packs for vintage sets), enjoy the experience, then if you didn't hit Gyarados-GX in the box, buy the single for $25.80. A 36-pack box delivers a probability of 1 − (1 − p)³⁶ ≈ 36.0% of pulling Gyarados-GX at least once, where p is the per-pack hit rate of 0.012333. So a sealed box gives you roughly a 36% chance of hitting this card "for free" alongside the rest of the box contents, plus the rip experience. If you miss, you backstop by buying the single — total worst-case cost is the box price plus the single. Most rational hobbyists end here.

The expensive path is pure-rip-to-pull: keep opening packs until Gyarados-GX appears. The expected total cost is ~$405, but the 95th percentile pushes that to ~$1,210. Almost nobody who does this comes out ahead financially — but it produces the binder story, the YouTube content, and the cumulative pulls of the entire pack contents along the way. If your real goal is collecting all of Crimson Invasion, not just acquiring Gyarados-GX, the pure-rip path has an internal logic the singles path doesn't.

Variance is the entire story

Here's a concrete illustration of how wild the geometric distribution gets at low p. Consider 10 hypothetical openers all chasing Gyarados-GX from Crimson Invasion. Mathematically, you'd expect their results to cluster near the 82-pack expectation — but they won't. Roughly 5 will pull Gyarados-GX within the first 56 packs and feel lucky. Roughly 3 will pull between 56 and 82 packs and feel "about average". And roughly 2 will be still pulling past pack 82, with one of them potentially stretching past the 95% bound of 242. The unlucky ones will swear the simulator is rigged, the rates are wrong, or that they have terrible RNG — but the math says exactly this distribution should happen every time. The geometric distribution has no memory: each pack is an independent draw, and a 100-pack dry streak does not increase the odds of the next pack hitting.

How Gyarados-GX compares to the broader Crimson Invasion chase pool

Gyarados-GX sits in the GX tier of Crimson Invasion's rare-slot pool. 9 cards share this tier, and the tier itself fires roughly 11.10% of the time per pack. That means the per-pack chance of pulling any GX card (not just Gyarados-GX) is 11.10%, which makes the expected wait for any GX card much shorter than the wait for this specific one. Pull-rate intuition: a single chase from a 6-card tier is 6× rarer than the tier itself. The deeper the pool, the longer the chase. This is also why "wide" sets with many chase cards in a single tier feel grindier per individual card despite the tier hit rate being identical — a thicker tier dilutes each card's specific share.

If your real goal is "any chase card from Crimson Invasion" rather than "Gyarados-GX specifically", the math gets dramatically friendlier — the wait drops to ~10 packs on average for the tier as a whole. Most binder collectors approach it this way: chase the tier broadly across multiple sets, accept whatever pulls, and snipe the specific holes via TCGplayer later. Targeting one card from a thick tier is the most expensive way to play the chase, and Gyarados-GX is no exception.