Doesnt sound like Damping Off to me. Where are you located that you can start seedlings in the garage at this time of year?

I live in walking distance to the beach on the MS gulf coast. The warm water keeps us out of freezing temps like 99% of the time. Just a couple miles north dips in temps dramatically. With that, grow lights, and a heat pad I'm feeling pretty confident in a really early start (hell, I've got experimental Roma toms setting fruit in the green house right now), or I may be setting up for a huge disaster, either way, everyone will be kept up to date along the way :).

Here's that pic I was promising:

Mice?

Hmm... I haven't seen any droppings but also haven't been looking for them Good call, I'll have check in the morning. Thanks!

I know rats LOVE seedlings.
I dont know if you have any slugs/snails this time of the year.

I had that happening in my greenhouse a couple of years ago. I figured it was mice or crickets. Those were the only pests in there that I could find. I do know, when I killed the crickets (there were only two) it stopped.
Pam

No slugs or snails in the garage... I didn't see any mouse poo either... Whatever this little bugger is he's slick. But no new damage so that's good.

Have you got a clear plastic bag that you can use to build a little tent over them?

Maybe that would stop whatever monster is using your seedlings for salad.

I've got one of the greenhouse domes but I don't want to stop air circulation. It's only munched on a couple and I have another tray almost ready to transplant and hasn't chewed on any of them. It's been more of a mystery than a nuisance. Thank you again everyone for the input! I think I have a few sticky traps hanging around, I may see what I can catch :)

You could try some tule fabric over the top of them if they are that small.
Bruce

What's a lot easier is - get thee to a dollar store and buy some of those little netted umbrella domes that most people put over food at picnics.
I'm using one of hose right now, covered in plastic as a cloche to stop the heat in the greenhouse from reaching my lettuce!