eves needle

Austrocylindropuntia subulata known as Eve's Needle, it does look like. And yes letting it callous over will a must. Plant it in soil after and wait for roots before you water. Waiting is the hardest part because you'll instinctively want to try and help it out with water but you'll only end up rotting it if you water it too soon. It may even wrinkle before it grows roots.

I have one just like it. For me its been a very hardy plant and does extremely well in captivity. I'm hoping it will flower this year. :)