Metal sounding 'clunk' noise when starting 4Runner

[ZMAN]

Well heck, this isn't the way I wanted to start my weekend. Curious if anyone else has come across this peculiar issue with their Toyota 4Runner: Occasionally, right after ignition, there's this distinct metallic clunk noise. It's not a regular occurrence, but when it does rear its head, it's quite noticeable, sounding like a clash of metal against metal, audible both inside and outside the vehicle.

I'm at a lose here and could use some help identifying. Thank you

 

[Ramrock]

Is it happening when you put the truck into gear? Also have you checked the exhaust?

 

[ZMAN]

Thank you, but no. It happens right after ignition.