Your first link to metroid actually goes to the IC page for some reason.

I'd just add a couple of things about the immune to weaponry part (garnered from the wiki):
"Sensitivity to certain sonic frequencies" - http://metroid.wikia.com/wiki/Metroid_(species)#Physiology_and_morphology, toward the bottom of the section.
And I imagine that X-Ray lasers can damage them, more-or-less, based off of Samus' use of the Nova beam to kill phazon metroids by aiming at their... nuclei(?). According to the wiki, it's a "high-frequency electromagnetic radiation beam" weapon, which means X-Rays or Gamma rays. Not that, I think, anybody's going to get X-Ray lasers any time soon.

[hider=Interesting thing about X-Rays.]
They tend to get absorbed, rather than reflected, by mirrors that are at standard angles. So, [url=http://imagine.gsfc.nasa.gov/docs/science/how_l1/xray_telescopes.html]to make an X-Ray telescope[/url], they use [url=http://imagine.gsfc.nasa.gov/Images/science/xray_focus.gif]grazing mirrors[/url]. X-Ray lasers, therefore, don't have [url=http://en.wikipedia.org/wiki/Optical_cavity]resonators[/url] (ususally), which means there's less [url=http://en.wikipedia.org/wiki/Coherence_(physics)#Spatial_coherence]coherence[/url]. This has no relevence to anything whatsoever, I just thought it was fascinating.[/hider]

Anyway, you're accepted! Throw up an intro post when you're ready.