That's neat, a girl that actually likes spiders, that's different, sounds like an interesting little hobby. Do you let them go or step on them? I imagine you let them go!
If I had to guess about your pill, I'd guess it's an OTC something or another, here's the only listing I've found for MK, but as you see it is imprinted.
http://www.pharmer.org/images/foreign/diazepam-mk-dz