Brush tool gives weird stamp that looks like a penguin?

[jmbiene]

I'm definitely a novice so my apologies if this is obvious. I'm trying to whiten a subject's eyes in a photo. I'm going through steps I found here https://www.adobe.com/creativecloud/photography/hub/guides/how-to-brighten-eyes-in-photoshop.html , but when I get to this step the brush tool doesn't work and i get what looks like a stamp of a penguin? 

What is happening lol.

[Bojan Živković]

It is probably brush preset choice. You should choose proper brush for the task. Right click while Brush tool is active is probably easiest way to acess brush preset list.

[Trevor.Dennis]

The easiest way to fix weird behaviour all at once, is to reset the tool.  This will take you back to a round preset with normal blend mode.