So, Catastrophe is out of surgery and will be fine. The vet says there is no damage to her intestines at all. Her only problem appears to lie in her compulsive eating of hair ties.
Matt and I will be waking up extra early to take her to the regular vet so they can keep an eye on her while she recovers.
I will be placing all hair ties except the one(s) that are actively in my hair in the car or the yarn closet.
I need to stop adopting animals that eat inappropriate things. Maxx, the pit bull I share with my sister, knocked a good three years off of my life between eating DVDs, Advil (this necessitated a trip to the vet to get his stomach pumped), yarn, an entire roll of dental floss (at least his breath smelled good after that), hair ties (...sigh), bras, swimsuits, socks, washcloths (or anything made of terrycloth, really), bedsheets, sham covers, and much, much more. Once I revive my dead laptop, I'll post the full list.