Many years ago, the ping command had a bug that allowed malicious users to send malformed ping packets to a destination causing the issue.

Ping of death issue. This issue occurred due to a loophole that existed in the IPv4 ping packets which were originally intended to be 56-64 bytes in size. Some computers were not designed to handle packets that were bigger than this size. The sender would therefore send packets that were over 65,535 bytes with the aim of overwhelming the recipient. Upon receipt of this packet in the target computer, a buffer overflow would occur which would ultimately lead to a system crash and sometimes causing the implementation of harmful code.

What's the rest of it? lol