No Picnic Achievement in Halo: The Master Chief Collection

This achievement can be earned on the Easy difficulty (or higher) on Exodus.

At the very start of this mission, run down the ramp toward your primary objective. Before heading through a set of doors that leads you into a courtyard with a trio of Skirmishers, look around at the ground in front of said building; there are several dead bodies and a small teddy bear backpack. All you need to do is look at this backpack for a few seconds and the achievement will unlock.