Fight the Leprechaun

You meet the leprechaun in a neutral area, a place where no innocent or guilty bystanders are likely to get hurt.

"At last you have decided to meet your fate with honor, you coward." The leprechaun shouts to you.

"Do you expect me to come back to you?" you respond.

"No, stupid! I expect you to die!"

With that the leprechaun rushes you with impressive speed, using the secret special leprechaun technique: Rainbow Ender! How should you react?!