Strange yarns

Good morning, and happy Monday!!!

I thought this morning I'd share something strange I came across while reading the Lion Brand email newsletter: stainless steel yarn.

Yes, you read that correctly (although you may want to do as I did, and click through the link above to confirm that your eyes are properly interpreting the letters above). This yarn is 75% wool and 25% STAINLESS STEEL.

I wonder how soft that is? Is there any real drape to steel? Does it relax/soften more with washing? Or with insertion into a VERY HOT FURNACE??? LOL

Actually, it got me to wondering about other strange materials used for yarns. Here are some I've found (each with a few brand examples), some stranger than others:

possum (there were several, I just picked one)
milk (tell me, do your projects curdle if not refrigerated?)
newspaper (this one you can spin yourself, although it looks very time-consuming)
pre- & post-consumer recycled yarn (this yarn made from waste poly-fibers and post-consumer plastic bottles isn't available, as far as I can tell, for us hand-knitters, but is interesting nonetheless)

What odd yarns have you seen/heard about? Anyone know anything about "concrete" yarn? I swear I saw it in passing one day, but I can't find information on it anywhere.