To determine a spell's total cost, start with the mana cost (or an alternative cost if another card's effect allows you to pay one instead), add any cost increases (such as kicker), then apply any cost reductions
A lot of what makes a core set fun to play is the way that it returns players to bread-and-butter, creature-based Magic , with interesting decision points in combat and a lower level of mechanical complexity
It would be in the running for the most commonly played uncommon of all time
But that's kind of a win more thing, and on top of it you have to protect a bunch of 2/2s, and 2 toughness is notoriously easy to take out
Then, by paying two generic mana, the Incubator will transform into a Phyrexian creature with those counters on it