"go mental" meaning in English

{
  "forms": [
    {
      "form": "goes mental",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "going mental",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "went mental",
      "tags": [
        "past"
      ]
    },
    {
      "form": "gone mental",
      "tags": [
        "participle",
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "go<goes,,went,gone> mental"
      },
      "expansion": "go mental (third-person singular simple present goes mental, present participle going mental, simple past went mental, past participle gone mental)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "_dis": "45 55",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "49 51",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "51 49",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "examples": [
        {
          "text": "Her father went mental when he found out that she was pregnant.",
          "type": "example"
        }
      ],
      "glosses": [
        "To become extremely angry."
      ],
      "id": "en-go_mental-en-verb-R~1P6inQ",
      "raw_glosses": [
        "(informal) To become extremely angry."
      ],
      "tags": [
        "informal"
      ]
    },
    {
      "categories": [
        {
          "_dis": "45 55",
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w+disamb"
        },
        {
          "_dis": "49 51",
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w+disamb"
        },
        {
          "_dis": "51 49",
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w+disamb"
        }
      ],
      "examples": [
        {
          "text": "When the band came on stage, the crowd went mental.",
          "type": "example"
        }
      ],
      "glosses": [
        "To become wild with excitement."
      ],
      "id": "en-go_mental-en-verb-uiH21Fic",
      "raw_glosses": [
        "(informal) To become wild with excitement."
      ],
      "tags": [
        "informal"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "LL-Q1860 (eng)-Flame, not lame-go mental.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/7/7a/LL-Q1860_%28eng%29-Flame%2C_not_lame-go_mental.wav/LL-Q1860_%28eng%29-Flame%2C_not_lame-go_mental.wav.mp3",
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    }
  ],
  "word": "go mental"
}

{
  "categories": [
    "English entries with incorrect language header",
    "English lemmas",
    "English multiword terms",
    "English verbs",
    "Pages with 1 entry",
    "Pages with entries"
  ],
  "forms": [
    {
      "form": "goes mental",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "going mental",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "went mental",
      "tags": [
        "past"
      ]
    },
    {
      "form": "gone mental",
      "tags": [
        "participle",
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "go<goes,,went,gone> mental"
      },
      "expansion": "go mental (third-person singular simple present goes mental, present participle going mental, simple past went mental, past participle gone mental)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        "English informal terms",
        "English terms with usage examples"
      ],
      "examples": [
        {
          "text": "Her father went mental when he found out that she was pregnant.",
          "type": "example"
        }
      ],
      "glosses": [
        "To become extremely angry."
      ],
      "raw_glosses": [
        "(informal) To become extremely angry."
      ],
      "tags": [
        "informal"
      ]
    },
    {
      "categories": [
        "English informal terms",
        "English terms with usage examples"
      ],
      "examples": [
        {
          "text": "When the band came on stage, the crowd went mental.",
          "type": "example"
        }
      ],
      "glosses": [
        "To become wild with excitement."
      ],
      "raw_glosses": [
        "(informal) To become wild with excitement."
      ],
      "tags": [
        "informal"
      ]
    }
  ],
  "sounds": [
    {
      "audio": "LL-Q1860 (eng)-Flame, not lame-go mental.wav",
      "mp3_url": "https://upload.wikimedia.org/wikipedia/commons/transcoded/7/7a/LL-Q1860_%28eng%29-Flame%2C_not_lame-go_mental.wav/LL-Q1860_%28eng%29-Flame%2C_not_lame-go_mental.wav.mp3",
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    }
  ],
  "word": "go mental"
}