170,000-Year Magicicada Nymph (17万年ゼミ幼虫, 17 Man-nen Zemi Yōchū) was a large Mysterious Being that attacked Z-City at some point during Saitama's training years.
The Magicicada Nymph is a massive cicada, that has the face of a child located at the center of its head, between its eyes.
During Saitama's training years, the Magicicada Nymph attacks Z-City and defeats two C-Class heroes Grad School Graduate and Red Muffler and B-Class hero Darkness Blade with ease while the rest of the population barricades itself within Shelter Nr. 7. Sometimes later two unnamed A-Class heroes try to fight it, but are also defeated, this causes the Hero Association to declare it as a Demon level threat and they decide to send one of their newly built subjugation squads to finish it off. Saitama, while running around in search of a bathroom, runs into the Nymph who suddenly attacks him, but falls victim to Saitama's punch.
Powers and Stats
Tier: Unknown. Likely 7-B
Name: 170,000 Year Magicicada Nymph
Origin: One-Punch Man
Age: As the name implies 170,000
Classification: Monster, Demon Level Threat
Powers and Abilities: Superhuman Psychical Characteristics
Attack Potency: Unknown. Likely City level (Should likely be comparable to other Demon level threats)
Lifting Strength: Unknown
Striking Strength: Unknown. Likely Class PJ
Durability: Unknown. Likely City level
Range: Several meters by sheer size
Standard Equipment: None
Intelligence: At least Below Average