Trundle bug

Well I don't know if it's a bug or not but I was fighting Zac earlier with Trundle and I started attacking him and I used my E, moments later he stood entirely still and I just killed him multiple times, however I don't know how to actually use the glitch, if it even is a glitch.

The incident was entirely innocent of malicious intent and I don't intend to get banned from this. Just letting you guys know how and why it happened if I was reported as someone did accuse me of using a lag switch which I don't have any knowledge of.