Once the countdown begins, you don't even need to attacksimply drop Atraxa and cast spells like Experimental Augury or Tezzeret's Gambit to draw cards and proliferate
While they were in the set as individual cards at vision design handoff, hearing so much support for them ensured their place in the set and inspired me to put them on the same card since they were so often talked about together
Im not sure why, but Quasiduplicate is templated as choosing a target and this just copies a creature on resolution, so your opponent can counter Quasiduplicate with a removal spell, but if you have multiple creatures on the battlefield, theyd need to kill all of them to counter this, which actually makes it a lot safer to use in Constructed Magic
But they gradually fixed the problem, finally streamlining the process with X &Y
It also puts 10 power into play for five mana, which synergizes nicely with a lot of cards in Animated Army