Vzwpix.co - iPhone sent message by itself

I saw this on my xfinity app from this morning:

outgoing xxxxxxxxxx@vzwpix.co 5:19:13 AM ESTMultimedia

What does this mean? The actual phone number is to someone I don’t know and I wasn’t even awake at this time. It also says .co and not .com. I didn’t send any multimedia message to anyone on vzwpix and I probably never have. I don’t have that phone number in my emails or my iPhone contacts. I scanned my phone and it didn’t result in anything suspicious. What now?