With Spring Ball alone, quickly jump over the Kihunter and wait for it to move away, then Spring Ball Bomb Jump through the door. Alternatively, place a Power Bomb and roll to the left on entry to kill the Kihunter, then quickly IBJ through the door before more arrive.

Entrance condition:

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

Requires:

{
  "or": [
    "canTrickyJump",
    {
      "enemyDamage": {
        "enemy": "Kihunter (green)",
        "type": "contact",
        "hits": 1
      }
    }
  ]
}
{
  "or": [
    "h_artificialMorphSpringBallBombJump",
    {
      "and": [
        "h_artificialMorphSpringBall",
        "HiJump"
      ]
    },
    {
      "and": [
        "h_artificialMorphIBJ",
        "h_artificialMorphPowerBomb"
      ]
    },
    "Morph"
  ]
}

Exit condition:

{
  "leaveWithGMode": {
    "morphed": true
  }
}

Dev note: It is possible to do this with Bombs alone, but it is pretty chaotic.