Unfortunately, being kept in a box where it won't be crushed by anything else is pretty much your only option, aside from sitting it on a wig head somewhere in your room, staring at you soullessly as you go to sleep every night.
I've stored heavily spiked wigs in shoeboxes before and haven't had a problem with them otherwise. I just gently place the hair net the original wig came with over it and carefully place it inside to make sure it's not getting squished. Depending on how long you store it and what product you use, you might need to touch up the spikes a with a bit of product the next time you use it.
Katsucon ~ Zenkaikon ~ Otakon