Could you give me a concrete example?

To me, it sounds like you are describing a naked short call, or a short put.

It is not a spread. By definition, spreads have limited risk, and limited rewards.

The four main types of spreads. Take a look at the PNL diagrams. It is limited risk. https://www.optionseducation.org/strategies_advanced_concept... https://www.optionseducation.org/strategies_advanced_concept... https://www.optionseducation.org/strategies_advanced_concept... https://www.optionseducation.org/strategies_advanced_concept...