Hatchery Sliver is your solution
In hindsight, this was an incredible deal, and it certainly seemed like Bottle-Cap Blast was somewhat slept on
Of course, having access to all five colors, Progenitus decks are versatile and diverse
The BFL8 for Cups and Challenges has me confused and disappointed at this point, as the yearly BFL for those along with the decrease in NA CP required for Worlds were two positive changes that the community wanted/needed
The biggest downside is that its fragile body needs to survive, but the upside is giant considering that you dont need to do anything else to copy the spell
Especially since the printings of Ragavan, Nimble Pilferer and Dragons Rage Channeler, the steal a casting cost 1 nonland-permanent mode has become very important and overall buffed the playability of the card