Its incredibly rare for any card to sustain a post-spike price for long, especially when some of those spikes were 300-400% increases in value
While this isn't the first time the Pokmon TCG promotion has been available in South America, with Suriname running it way back in March, this is by far the most widespread launch of the cards on the continent

Abandoned Air Temple Abzan Ascendancy Action News Crew Ajani Goldmane Ajani Steadfast Ajani, the Greathearted Andril, Narsil Reforged Arcbound Overseer Archangel of Thune Archangel of Thune Aron, Benalia's Ruin Atmospheric Greenhouse Barrensteppe Siege Basri Ket Basri's Solidarity Borborygmos Brokers Ascendancy Cathars' Crusade Celes, Rune Knight Celestial Ancient Colonel Autumn Cooking Campsite Cosmogrand Zenith Dawnstrike Vanguard Defiler of Vigor Dueling Coach Durable Handicraft Duskfang Mentor Duty Beyond Death Elrond of the White Council Elspeth, Storm Slayer Felidar Retreat Felothar, Dawn of the Abzan Fire Lord Zuko Fire Nation Sentinels Flopsie, Bumi's Buddy Frillscare Mentor Galadriel, Light of Valinor Gavony Township Genku, Future Shaper Gideon's Battle Cry Gourmand's Talent Greenbelt Radical Hornbash Mentor Hylda of the Icy Crown Inspiring Roar Invasion of Moag Katilda, Dawnhart Prime Keensight Mentor Kellan Joins Up Kibo, Uktabi Prince Leader's Talent Leading Performance Leonardo, the Balance Leyline of Abundance Lifecrafter's Gift Lisette, Dean of the Root Littjara Loyal Guardian Mayael's Aria Mazirek, Kraul Death Priest Methods of the Mighty Misfortune Munda's Vanguard Nalia de'Arnise Nissa, Voice of Zendikar Nita, Forum Conciliator Now for Wrath, Now for Ruin

Since Gold Rare cards have essentially been retired, the occasional price spike featuring cards bearing that rarity such as this Chaos Sorcerer card should be somewhat expected
If this card is banished from your GY: You can make Special Summoned monsters your opponent currently controls lose 400 ATK for each Cyberse monster currently in your GY, until the end of this turn