What is this?

 

Looks like the air tube from the outerbody to the air filter.

 

That is the cowl drain valve/boot. It attaches to the bottom of the cowl on the firewall in the engine bay area. I replaced mine a couple years ago because it rotted and started to fall apart like the one in your picture.You can force it up from the bottom through the hole, but it's much easier to replace from the top if you remove the cabin air filter access panel.

The part number is 15825905 and costs about $10 to replace. The parts personnel at the dealership will thank you for the part number because it's very difficult to find in the parts diagrams unless they've looked one up before and know exactly where to look.

This exact same part is used on the Saturn Vue (1st gen 2002-2007), Chevrolet Equinox (1st and 2nd gen 2005-2017), Pontiac Torrent (2006-2009), and GMC Terrain (2010-2017).