Weta water...

I left my sipper cup, with just tap water in it, on my home office desk overnight. Opened it to refill the next morning to find someone, must have squeezed through the open sip gap, had moved in overnight!

Presume it came in the office window, which was ajar and has a bark fern garden outside, looking for a drink?

Although a bit pale and puffy looking it was still alive. In my haste to save I didn't take a photo (thus the recreation above). After some time on a garden branch basking in the morning sun, it wandered off seemingly OK. Always check your cup!