From Halopedia, the Halo wiki
No Picnic is an achievement in the Halo: The Master Chief Collection port of Halo: Reach. The achievement is unlocked by looking at the teddy bear backpack near the exit doors of the boardwalk at the beginning of the level Exodus.
The achievement's in-game description erroneously states "Observe a grizzly scene on New Alexandria." It should more accurately say "in New Alexandria" or "on Exodus."