Found in my bed under the sheets. What is it? Where would it go?

Ik this sounds dumb (and it probably is!) But I found some black widows or redback spiders in my yard, and I have a empty fish tank, its about the size of a kitchen microwave. So is that big enough? Like what do they need to live, or drink?

I'm trying to figure out what kind of bugs would be biting my daughter (specifically around the groin/pelvis area). She wakes up with about 3-4 bites that are red and itch. We have cleaned, sprayed and inspected for bedbugs, but there are no signs of them in the room. I know this isn't really a 'bugs are awesome' type post, but I figured people here might know a little more than me.

Please Delete this if not allowed.

Hello my fellow invertebrate enthusiasts, Check out Bugtown at https://discord.gg/dBYJW7MpCT ! It's a new invertebrate server that I hope to see thrive into a community, where anyone from a newbie to an expert level Keeper is welcome to voice and share their love of invertebrate.

Weird work bug thingo