Warped

From publisher blurb:

Warped is a simple Q-Encounter to be dropped during a rest at one of the currier stations found throughout the Kingdom of Castiel. During the night, a gate from the Shadow Realm awakens after goblins stumble upon an artifact, opening a door to the Material Plane. With their inability to stabilize the gate, a few daring long-toothed goblins step through only to discover the gate is distorted, a passage that warps anything that passes through.

Warped is a Q-Encounter, or Quick-Encounter, that can be run for a group of four to six players with 2nd-level characters. This encounter would be considered a ‘medium’ to ‘hard’ encounter.