Supernatural
な adjective
Something that is ultra natural (自然的) is supernatural. Too natural! Super!
ちょうしぜんてき
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
そういえば、私の超自然的な力についてお話したことってありましたっけ？
Have I ever told you about my supernatural power?