sudden infant dog syndrome

Last night Penny looked cold in the bed so Adam covered her up with the fleece blanket that covers her bed. I didn't like the way he wrapped the blanket around her head because she had no way of breathing so I said "She is going to be breathing in carbon monoxide...you know, like SIDS."
Adam:  SIDS?
me: Sudden Infant Death Syndrome
Adam: Sudden Infant Dog Syndrome

And then we both lost it.  Adam was laughing so hard that he was crying.  We laughed seriously for 10 minutes straight, and then when Adam laid down to sleep while I read, he started laughing again.  So I said, "Really?  Why are we laughing about this?"
Adam:  I don't know.  It just doesn't make any sense, but when I said it, I thought it did.

And then we laughed more about it for a while.

But honestly, is it really that funny?  This morning I was thinking that it really wasn't that funny.  Yet we continue to laugh about it.

**Disclaimer:  We don't think SIDS is a laughing matter at all, having had an infant ourselves.  It is just funny that Adam thought he was making a joke, but instead he said something that made no sense whatsoever.