DrZhark’s CustomSpawner represents ~ 43 % of the total tick time and Sponge’s TrackingUtil (entities and tile entities in this case) represents ~ 32 %. My theory is that DrZhark’s CustomSpawner try to spawn new entities that your plugin cancels so it try again and again … causing the server to lag. This explains both DrZhark’s CustomSpawner and Sponge’s TrackingUtil tick time. You should take a look at DrZhark’s CustomSpawner sources to check whether it’s true or not. And open an issue on his github page if it is. Also, use the latest version of SpongeForge (not necessarily the recommend one), there have been optimizations recently.