The pre-Essentials 4e trap/hazard stat blocks used the "origin" slot—under the name, corresponding to the "Size origin (keywords), race" line on a monster stat block—to categorize the feature as a trap or hazard, and used the "level/role" slot to assign traps various roles ("blaster," "obstacle," and so on). For example, in the DMG:
|Spear Gauntlet||Level 2 Obstacle|
The Essentials trap/hazard stat block as shown in the Rules Compendium, however, now uses "Trap" or "Hazard" as the role, and all the examples I've seen so far have "Object" in the origin slot, like this one from the Rules Compendium:
|Spear Gauntlet||Level 2 Trap|
The "object" origin seems to bring with it some specific features, such as "Immune necrotic, poison, psychic, forced movement, all conditions, ongoing damage."
I own all the Essentials products except for the Dungeon Master's Kit. None of the products I own offer any guidelines for statting out traps using the Essentials sensibility, nor can I find any examples with origins other than "object." Do any such guidelines or examples appear in the Dungeon Master's Kit, or in any recent Dungeon or Dragon articles? I have searched but cannot find, and would appreciate any pointers.