Modern cleaned versions like those found on GitHub or archived by community members provide advanced combat tools without the security risks of the original:

DeimosClient/Deimos-Client: Phobos 1.9.0 Clean Buildable SRC.

Using any modified client on a server where it isn't allowed can lead to a permanent ban. These tools are strictly intended for anarchy servers where such modifications are part of the standard gameplay.

Are you planning to use this for or more for general travel on an anarchy server?

Open the Minecraft Launcher, select your Forge 1.12.2 profile, and start the game.

is a highly powerful utility mod for Minecraft 1.12.2 , originally developed for high-level Crystal PvP on anarchy servers like 2b2t . While the original 1.5.4 version is infamous for containing a Remote Access Trojan (RAT) that compromised thousands of users, the community has since produced "Clean" versions that have been audited to remove malicious code. Key Features of Clean Phobos

Includes BoatFly, Fast Swim, and various speed modules designed to bypass server-side anti-cheat on anarchy servers. How to Install Safely