After teleporting, as Samus swings to the right, begin holding down to extend Grapple just as Samus is slightly right of vertical. Samus should swing back left and get stuck on the floor one tile to the right of the Grapple attachment point. Release Grapple and Samus will clip through the floor.

Entrance condition:

{
  "comeInWithGrappleTeleport": {
    "blockPositions": [
      [
        5,
        3
      ]
    ]
  }
}

Requires:

{
  "heatFrames": 250
}
{
  "or": [
    "canWalljump",
    "h_canCrouchJumpDownGrab"
  ]
}