Survivor.io is mobile gaming’s latest out-of-nowhere success, topping iOS and Android charts throughout August. It got there with an eyebrow-raising gameplay concept and popular ads on TikTok.

Why it matters: Mobile is the game industry's biggest market, but chart-topping hits are often big surprises that call for some sleuthing about how they blew up.

Details: Survivor.io puts players in control of a tiny warrior who automatically attacks swarms of enemies as they approach. The player races to upgrade their fighter’s firepower to keep up.

Driving the news: Video game consultancy group Naavik has noted that Survivor.io has been heavily advertised on TikTok and suggests it's "one of the first success cases for games x TikTok ads."

The big picture: For avid PC gamers, Survivor.io may remind them of the equally captivating late 2021 breakout hit Vampire Survivors, but without the vampires.

Between the lines: Survivor.io is developed by Gorilla Game Studio and published by Habby, which had another hit game with auto-firing combat Archero in 2019.

Sign up for the Axios Gaming newsletter here.