Yoshi's Island/Headscratchers

• Can anyone think up a reason, besides pissing off the player, as to why Yoshi dies if he so much as brushes any kind of spike?
  • They give him really bad tetanus?
  • Baby Bowser got them from Dr. Wily?
  • Poisoned, maybe?
  • He actually gets hurt by them, just like falling off the screen, whereas getting hit by anything else merely knocks the baby from his back?
    • When Yoshi gets hit by an enemy while carrying Mario in Super Mario World, the plumber merely falls off his back. Maybe it's a Continuity Nod.
• What exactly do these "stars" do in Yoshi's Island DS? I mean as in the star children; the reason Bowser goes back in time. What do they do? Does it give them some kind of power or something. It was rather ambiguous.
  • It... gives them top billing in the series, including spinoffs? Maybe it's more than that, but I wouldn't know. Still, I'm fond of the theory that the seventh star child, a green Yoshi, was granted the ability to speak properly. Thus he's the fluent Yoshi seen in a number of earlier games, most notably Super Mario RPG, where he serves as a translator.
  • (Original Poster) I believe that the green Yoshi who is the seventh star child is THE Yoshi, and it makes sense (they wouldn't just make it a random Yoshi). But is it officially him?
  • Well, Bowser stated that the power the stars would give him would enable him to take over the universe, so I guess that's the answer...