It's responsible for many explosive starts, which is why it's often an auto-include, and (presumably) why Frank included it but no additional ramp when doing the math on his Lands count
Well, this is one of the densest settings Wizards of the Coast has released in recent years, full of factions and different alien species, but we'll do our best to summarize
Mana Crypt costs zero to cast and immediately generates two mana which recurs every turn, though it has a chance of dealing three damage to you on your upkeep, a downside far outweighed by the absolutely ludicrous upside
By design, infect counters are nearly impossible to remove, but Leeches are the way to do it
Illustrated by Lake Hurwitz
If you played without any ones or twos, you could guarantee your cascades always hit a Hypergenesis, which, despite having no cost, counts as zero cost for cascade