As a teenager, Pokemon creator Satoshi Tajiri was so fond of collecting insects that classmates called him “Mr. Bug.” While it might not have been an affectionate label, Tajiri had the last laugh: His Pokemon video game, originally released for the Nintendo Game Boy in 1996, has become an enduring multimedia success, selling billions in games, merchandise, and phone apps.

The goal of collecting and pitting monsters against one another has been particularly appealing for trading card collectors, who have created an entire secondary market for the low-tech version of the game. First editions, misprints, and other characteristics all affect value. If you’re curious, take a look at the five most valuable Pokemon cards according to Heritage Auctions and other sources.

1. PIKACHU ILLUSTRATOR

stephychu025, eBay

One of the earliest cards to come out of the Pokemon franchise was this promotional card of Pikachu that was given out to winners of an illustration contest in 1998. An estimated 20 to 39 copies were issued. In late 2016, Heritage Auctions sold one for a whopping $54,970. In 2017, an eBay seller was asking $100,000 for a card graded by professional authenticators to be in virtually perfect condition.

2. CHARIZARD

bakemat_0, eBay

This dragon-esque creature was first seen in 1999. Nearly 20 years later, a perfect “10” graded card sold for $11,999.  

3. MASTER’S KEY PRIZE CARD

ebirdman, eBay

Given out during a 2010 card championship in Japan, only 34 copies of the Master's Key Prize Card are thought to exist. The scarcity helps the cards fetch four figures when they're spotted on the open market.

4. PRE-RELEASE RAICHU

sken1851, eBay

Collectors love cards that were never intended for public distribution, and this Raichu card fits the bill. Although unconfirmed, Pokemon lore has it that product distributor Wizards of the Coast made just 10 of these Raichu cards for their employees and stamped “pre release” on the front. While it’s rarely offered for sale, collectors believe it can fetch up to $10,000.

5. POKEMON SNAP CARDS

base_set_sales, eBay

In a bit of product synergy, Nintendo’s 1999 N64 game, Pokemon Snap, ran a promotion in which players could take a “candid” shot of Pokemon in the game and send it in to a Japanese magazine. Winners would have the image placed on a card. Due to their rarity, the Snaps have reportedly sold for over $8000.