YOU SAID:

My mum took me to a party dressed as a unicorn.

INTO JAPANESE

母は私をユニコーンに扮したパーティーに連れて行きました。

BACK INTO ENGLISH

My mother took me to a party dressed as a unicorn.

INTO JAPANESE

母は私をユニコーンに扮したパーティーに連れて行った。

BACK INTO ENGLISH

My mother took me to a party dressed as a unicorn.