Fake urgency
The user is pressured into completing an action because they are presented with a fake time limitation.
Definition
When a user is placed under time pressure, they are less able to critically evaluate the information shown to them because they have less time and may experience anxiety or stress. Providers can use this to their advantage, to push them into completing an action that may not entirely be in the user's interest.
Example
The Shopify app “Hurrify” is made by a company called Twozillas. It can be used to create various fake urgency messages, one of which is a fake countdown timer. In the first image, you can see what a user typically sees on a site that uses the Hurrify countdown timer. It's very prominent, animated and claims that the sale will end once the timer hits zero. However, the admin interface for sellers (second image) has a default configuration to "Run the campaign allover again" which means that the counter simply resets when it reaches zero.
Update April 2023: Hurrify appears to have been banned from the Shopify app store.
1 / 218 examples in the hall of shame
References
Countdown timer (Mathur et al., 2019), limited time message (Mathur et al., 2019).