your opponent cannot target it with card effects this turn
Diving into the most expensive realms of the Pokemon Trading Card Game is in some ways simply par for the course
We also needed something for chocobos to do, and the saddle mechanic didn't exist yet due to the development timelines of Outlaws of Thunder Junction and Aetherdrift
The four-of maximum was quickly added to the rules to avoid this, and Black Lotus and Channel were later restricted or banned in their environments to make this even less likely
You can technically build GU as two colors, but there are many incentives to play at least three as you draft the towns archetype
First of all, "Catalyst Field" allows the Normal Summon of higher Level Gemini monsters without Tribute, which allows cards like the "Poly-Chemicritters", "Phoenix Gearfried" or "Darkstorm Dragon" to be put on the field without a huge minus in card economy