An eclipse attack is a type of attack on a blockchain network where an attacker attempts to isolate a particular node or a group of nodes by controlling all of its incoming and outgoing connections. By doing so, the attacker can feed the victim node(s) false information, potentially leading to various types of manipulation, such as preventing the victim from receiving valid transactions or propagating malicious transactions to the victim's peers. This can disrupt the victim's ability to participate effectively in the network, compromising its security and integrity.