The crab will not come through the whole tunnel, so wait for it to pass before going through the vertical portion.

Entrance condition:

{
  "comeInWithGMode": {
    "mode": "any",
    "morphed": true
  }
}

Requires:

{
  "or": [
    "h_artificialMorphSpringBall",
    {
      "and": [
        "Gravity",
        "h_artificialMorphBombThings"
      ]
    }
  ]
}

Dev note: The tunnel does not need to be expanded for Samus to get into the morph tunnel without getting stuck, regardless of if she has Morph or artificial morph, and is in direct or indirect G-mode.