Invalid clicks on Google Ads are clicks on ads that are considered illegitimate or fraudulent. These clicks can be generated by automated clicking tools, manual clicks by someone repeatedly clicking on ads, or other malicious behavior. Here are some of the types of invalid clicks that can occur on Google Ads:

1. Clicks from automated clicking tools: These are clicks generated by software or bots that simulate real user behavior.
2. Clicks from manual clicking: This is when someone repeatedly clicks on an ad, often with the intent to deplete the advertiser’s budget or to artificially increase clicks and impressions.
3. Clicks from competitors: Competitors may click on an ad to increase the cost for the advertiser or to reduce the effectiveness of the ad.
4. Clicks from click farms: Click farms are groups of people who are paid to click on ads to generate fraudulent clicks and impressions.
5. Clicks from incentivized clicks: Incentivized clicks occur when users are offered some kind of reward or incentive for clicking on an ad.
6. Clicks from accidental clicks: Accidental clicks occur when a user clicks on an ad accidentally or unintentionally.

Google has systems in place to detect and filter out invalid clicks, but it’s important for advertisers to monitor their ad campaigns regularly to detect any invalid clicks and take appropriate actions to prevent them.