170,000-Year-Old Cicada Adult

170,000-Year Magicicada Adult (17万年ゼミ成虫, Jūnana Man-nen Zemi Seichū) was a large Mysterious Being that attacked Z-City at some point during Saitama's training years. It was killed by Saitama.

Appearance
The Magicicada Adult was an extremely massive cicada-like creature, easily able to cast a large shadow over a city. Located at the center of it's head was a humanoid face.

Summer
170,000-Year Magicicada Adult attacks Z-City damaging many buildings. Saitama then appears before it and declares with a smile that summer has arrived.

Abilities and Powers
Since it was the grown up version of the 170,000-Year Magicicada Nymph, it was presumably much more powerful. Even S-Class heroes might have had difficulty dealing against it due to its resistant shell and its ability to fly.

Flight: The Magicicada Adult's wings allowed to fly.

Trivia

 * It bears a passing resemblance to the apostle Rosine in the grimdark fantasy manga Berserk.