Except for Thunder Dragon in Metal Raiders (2003), Thunder Dragon Colossus was the first member of the Thunder Dragon archetype to be announced (in Soul Fusion, 2018). However, even without an entire archetype to support it, this card is still an interesting one.
Thunder Dragon Colossus can be Fusion or Special Summoned by Tributing a Thunder Effect Monster, but only after resolving a Thunder monster’s effect in hand. This dragon also boasts of a powerful one-sided Mistake-like effect, all the while being able to protect itself from destruction by banishing a Thunder monster from the graveyard. Luckily, an entire archetype supporting Colossus and his brother Thunder Dragon Titan has prevented this card from becoming an obscure tech in Watts and Pendulum Magicians.
What is the deck that can consistently bring out three of their Fusion boss monsters and that shut down two of the best decks of the time, Gouki and Sky Striker? Thunder Dragons took nine out of the 32 spots at YCS Niagara Falls in 2018, making it the most popular deck out there. YCS London followed not much later, but Thunder Dragon decks only took four spots there, and decks like Ping Xiao’s Sky Striker Trickstars might explain how this drop occurred: Players seemed to have been better prepared for the match-up, discarding any scepticism they may have had prior to YCS Niagara Falls. In spite of that setback, there were eight spots for Thunder Dragons at YCS Milan.
The changes in duelists' perspective on the Thunder Dragon deck are also reflected in the price tag of Thunder Dragon Colossus. Cards are always pretty hyped at Sneak Peek events. During that time, Colossus could have easily put 70,00 € to 80,00 € in your pocket, depending on how high demand at your locals was. Their great performance at YCS Niagara Falls kept the card hot, and it didn’t crash after its set officially released, as some high rarity cards do. It dropped naturally over the next few months, costing about 40,00 € to 50,00 € - a price decrease of more than 50 percent! The price perhaps might have dropped less if it hadn’t been for the other good secret rare, Danger!? Tsuchinoko? These were the two cards that duelists most wanted from Soul Fusion, the only expansion wherein the new Thunder Dragon cards are available.
The most obvious place to see Thunder Dragon Colossus is, of course, in Thunder Dragon decks – and there are many possible varieties in building it. While Thunder Dragonroar, Thunder Dragondark, and Thunder Dragonhawk are the typical cards duelists are playing in full playsets and the classic Thunder Dragon is also popular, the rest of the deck can look pretty different.
Thunder Dragonduo is an interesting addition that can help you push for a lot of damage. Including Brilliant Fusion and Instant Fusion help you to set up on turn 1 of a game. (The price spike on Gem-Knight Amber and Gem-Knight Prismaura can show you exactly when this was discovered.) A more stylish duelist can also throw in cards like Black Luster Soldier -Envoy of the Beginning or Chaos Emperor, the Dragon of Armageddon. Lastly, Denko Sekka and Batteryman Solar are also pleasant Normal Summons that can help you strengthen your turn 2 or turn 1 respectively.
Thunder Dragon Colossus can also be encountered in places where you would least expect it. Thunder decks like Watt, Hunder and Batteryman can splash in the regular Thunder Dragon or The Ascended of Thunder to bring out an actual threat. It’s almost a shame Thunder Seahorse prevents you from Special Summoning after using its Thunder Dragon-like effect. It is also perfectly possible to throw in a set of Thunder Dragons into your Pendulum deck. After searching for your second and third copy of it, you can discard one for a Pendulum Call and Pendulum Summon the other. One Tribute later, you get to add Thunder Dragon Colossus to your field that probably has a couple of negations already.
Overall, Thunder Dragon Colossus is an easy-to-summon boss monster for prominent decks in today’s format. Its price might make you think about it a bit, but it's not so expensive as to make it unplayable for the regular duelist.