Spawn a horde of zombies around the crate once it has landed.
Overrides per airdrop type, keyed by name (normal, bombing, ...).
Use the navmesh to drop at a random valid spot in the caller's grid cell.
Distance from the crate, in world units, the zombies spawn at.
Zombies spawned around each landed crate.
Spawn a horde of zombies around the crate once it has landed.