So the platypus is weird, right? It's a mammal, but it lays eggs. It secrets milk, but it doesn't have any nipples. It's got that big duck-looking beak, and for those really in the know, it's got a cloaca, a single opening for excretion and reproduction. It's also one of the few venomous mammals, with a spur on its hind legs that can inject venom. It's reportedly quite painful to be stung by a platypus. I wouldn't know. I've never had the privilege.
In a recent issue of the Journal of the American Chemical Society, Kita et al. report on some of the protein toxins present in platypus venom. One in particular is good at causing calcium influx in human nerve cells. They call it venom peptide 1 or heptapeptide 1. It's just seven amino acids (Histidine-Aspartate-Histidine-Proline-Asparagine-Proline-Arginine, abbreviated HDHPNPR), but it's a significant component of the venom and probably packs quite a punch.
What's the creationist application? I don't know. Natural evil? Intermediates and biological similarity? All of the above? I just like platypuses.
Kita et al. 2009. Duck-Billed Platypus Venom Peptides Induce Ca2+ Inﬂux in Neuroblastoma Cells. J. Am. Chem. Soc. 131:18038-18039.