Monster Time Bomb (怪獣時限爆弾 Kaijū Jigen Bakudan) is the eighth episode of Return of Ultraman.
A new monster surfaces in Hell Valley, and despite being a seemingly harmless creature, MAT must kill it anyways. Using Kishida's new X Bomb, Go is sent to do the job. Narrowly missing the monsters ray attack, Go fires, but the bomb doesn't go off. Upon reviewing the Arrow's on board flight recorder, Go set the bomb as a 10 hour timed blast instead of on-target detonation. Worried the creature may surface in a densely populated area before the bomb explodes, MAT must find the burrowing beast before the ten hours is up. Tensions are alleviated when it appears the creature is leaving the Tokyo area. But when it is learned the monster is heading towards a chemical dynamite factory in the Aoki Highlands, MAT rushes there to avert another potential disaster.
- Hideki Go (郷 秀樹 Gō Hideki): Jiro Dan (団 時朗 Dan Jirō)
- Takeshi Minami (南猛 Minami Takeshi): Shunsuke Ikeda (池田 駿介 Ikeda Shunsuke)
- Ippei Ueno (上野一平 Uneo Ippei): Mitsui Hatashi
- Yuriko Oka (丘ユリ子 Oka Yuriko): Mika Katsuragi (桂木美加 Katauragi Mika)
- Katsushiro Kato (加藤勝一郎 ): Nobuo Tsukamoto (塚本信夫 Tsukamoto Nobuo)
- Fumio Kishida (岸田文夫 Kishida Fumo): Nishida Ken (西田健 Ken Nishida)
- Jiro Sakata (坂田 次郎 Sakata Jirō): Kawaguchi Hideki (川口英樹 Hideki Kawaguchi)
- Aki Sakata (坂田アキ Sakata Aki): Rumi Sakakibara (榊原るみ Sakakibara Rumi)
- Ken Sakata (坂田健 Sakata Ken): Shin Kishida (岸田 森 Kishida Shin)
Return of Ultraman Vol.2 Episodes 5-8.