"According to evolutionists random mutations are what drives evolutionary change."
Well, that's one part of it, yes.
"But even they will admit that mutations alone are rare, let alone a mutation that is actually beneficiarry."
Mutations are anything but rare. Most mutations are neutral, a small portion can be harmful and another small portion are beneficial to the organism.
"Take fireflys for instance. I would imagine that the odds of a mutation that creates the light in fireflys to arise even just once would be pretty astronomical."
Well, yeah. But only if that's what you're aiming for in the first place. Evolution didn't have the bioluminescence of the firefly as the goal to achieve. Aside from that though, there are numerous species on the planet that use bioluminescence so it can't be all that "astronomical."
"But did you know that there are 2,000 different species of firefly? Now what are the odds that that same mutation appeared 2,000 times?"
It didn't you moron. That's what common descent means: they all had a common ancestor somewhere and that creature had the mutation that allows them to light up. Since the mutation is not harmful (other than possibly signaling to predators where you are) and is, overall, beneficial to the species, it was passed down even through speciation.
"That's like getting struck by lightning while winning the lottery simutanieusly 2,000 times!"
It certainly would be if your strawman were actually what happened. Unfortunately for you, it's not.
"It's amazing what absudities evolutionists will come up with ;)"
Try learning what "evolutionists" say to begin with before you begin critiquing them.
