If I transform an item, say Beaky for example, will I be able to transform it back to its original form? Or is the transformation permanent?

You can transform it back and forth whenever as long as you don't put the item into a collection, like

- Ah ok. Thank you! Just didn't want to buy it if I was going to get stuck with one version after transforming it.

items that say "transforms into" in the description can be transformed into any of the listed items, but those items cannot be transformed back into the original item. however, if the description says "transforms between" then all listed items can be infinitely transformed into one another. to be extra safe it's also best to check subetalodge when you're not sure.

I'm not seeing anything on Subetalodge that has "transforms into" in the description (except for a handful of items where it's just part of the text, but nothing like the "transforms between" notice)

I don't know of anything off hand that can't be transformed back except like, the Sphinx set in the MC but those aren't really transformable

If an item has the "transform" option, you can go back and forth as often as you want.

If an item has the "open," "use," "redeem" or other words for the option, then the effect is permanent.

hm i guess i'm misremembering, i could have sworn there were one-way transformables but it looks like they all have a "use" option instead. maybe it's been changed due to confusion.