Thought-Beasts are an animal species native to the planet Krypton. They are a feared predatory species, deadly to human and Kryptonian life. The thought beasts can project their thoughts onto screens on their foreheads, as an intimidation tactic. Additionally, they are capable of using telepathic attacks to distract their prey.
The main population of thought-beasts was presumably wiped out when the planet Krypton was destroyed. However, some have managed to survive, for example within the bottle city of Kandor.
On the planet New Krypton, there is a dangerous population of thought-beasts that survived Krypton's destruction within Kandor.
When Kal-El was serving in the Kryptonian military under General Zod, his first mission was to deal with an escaped herd of the beast by any means necessary. He was able to herd the creatures successfully. (World of New Krypton)