How much does Underdark Explorer cost
It's arguably one of the best cards for Type Four from the set (Rules are - infinite mana but just one spell per turn so counters are good there since they cannot be overwhelmed by casting more spells than you have mana, and a five cost counter is first turn able there)
Their success was monitored for a few years in Japan and the TCG was eventually released in North America in 1999 by Wizards of the Coast
As for the card, it's a copy of Akroma's Will, an instant that lets you choose between all your creatures gaining flying, vigilance, and double strike, or lifelink, indestructible, and protection from each color until the end of the turn
Just watch your life total
While the main set is only the mainline, numbered games, Secret Lair would have been the perfect opportunity to include games like Tactics, World of Final Fantasy, or maybe even Kingdom Hearts