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But just copying your foe's thing means you cannot Clone what your deck was built around - your stuff
Similarly, if The Soul Stone is already harnessed and becomes a copy of something else, it stays harnessed, though it's very likely that won't be relevant until that copy effect ends
Whether a creature dies or a player cracks and uses a Terramorphic Expanse or other fetch land, you draw and lose 1 life
More than anything, these moments seem to be self-perpetuating, where everyone gets tremendously excited about one particular card, which creates demand, which raises the price, which exaggerates the rarity, which creates demand The next most expensive right now is the Latias ex at almost $200, then the gold card version of the Pikachu ex at $100, and that Hydreigon pictured above at about $95
Aside from that, the following cards mention oozes in their rules text, including a few token generators: Convert to Slime Gelatinous Genesis Corrupted Zendikon Gutter Grime March of the World Ooze Miming Slime Mystic Genesis Ooze Flux Ooze Garden Slime Against Humanity Slime Molding Gutter Grime is a strong enchantment for a typal build, but Slime Against Humanity is fun since it lets you break deckbuilding rules