Modded mob seems to crash Minecraft

Okay, so I created a mob called the Slime Guide. It doesn't really cause any boxes that show it has an error though. I made 12 mods so far. Whenever I open Minecraft from the runClient button, it does well until some time. Later, it pauses and I try to move. It crashes and releases a "Gradle task failed" box. Somehow it started crashing after I spawned a Slime Guide (it has a boss bar). Can someone help the crashes? Does it have to do with my number of mods? Or the Slime Guide?