Capybara Clicker is an idle game about clicking a capybara. Each click earns capybaras; capybaras buy upgrades that earn more capybaras per click and per second; eventually the screen is full of capybaras in hats while numbers with too many digits tick upward. It is Cookie Clicker with a rodent, and the internet's affection for capybaras carried it to the top of school-Chromebook charts.
It plays in a background tab as well as it does in the foreground, saves in the browser, and offers the small pleasures idle games run on: a new outfit, a new weather effect, a new order of magnitude.
It saves your state and calculates offline earnings when you come back on the same device and browser. Earnings while away are usually capped, so a long absence is worth less than the same time with the tab open.
Whatever auto-earning upgrade you can afford right now. Per-second income compounds; per-click upgrades stop mattering once automation is running.
Yes — it is one of the lightest games on the site and runs in the browser with nothing to install, including in a background tab.