Brown Bats hibernate at this time of year so he probably was in your attic or chimney. They are usually harmless and should be left alone. Many bats are in trouble and protected by law. I have them around my house (outside) and I like having them there since they are good insect eaters and interesting to watch
Be careful however- bats can carry rabies (frequently) and if they bite you you need to get all the shots immediately. A few years ago a guy here in NJ did exactly what you are doing, holding a bat and later releasing it after finding it in his house. He got a minor scratch in the process. Since he never got the rabies shots he waited until it was too late and eventually died of rabies- one of the few cases recorded in the last ten years.
Normally bats avoid touching people. I'd be suspicious of one that was in the house acting strangely. Be careful.
WC
BTW- Crocs don't carry rabies- but if one bites you I doubt if you care about it anyway.