LeechModem was a BBS file transfer protocol client. LeechModem was compatible with protocols like XMODEM (and YMODEM), but it would mischievously NAK the last packet and then abort the file transfer.
LeechModem, a BBS file transfer protocol client, supported protocols such as XMODEM and YMODEM. However, it was known for its mischievous behavior of sending a NAK (Negative Acknowledgement) signal on the final packet, causing the transfer to abort.