Place Power Bombs to kill the Metroids. By hitting the first Rinka, all of the Metroids (on a similar vertical height to the Power Bomb) will be damaged.

Requires:

{
  "enemyKill": {
    "enemies": [
      [
        "Metroid",
        "Metroid",
        "Metroid"
      ]
    ],
    "explicitWeapons": [
      "PowerBombPeriphery"
    ]
  }
}
{
  "or": [
    "canTrickyJump",
    {
      "ammo": {
        "type": "PowerBomb",
        "count": 2
      }
    }
  ]
}
{
  "metroidFrames": 300
}

Clears obstacles: f_KilledMetroidRoom3

Sets flags: f_KilledMetroidRoom3

Dev note: Using 1 pack of PBs isn't intuitive as a way to kill 3 metroids without grouping them.