YOU SAID:

kirb rapidly changes his geological position by making a motion in his legs that causes him to move forwards

INTO JAPANESE

kirb は急速に前進する彼を引き起こす彼の足の動きを作る、彼の地質学的位置を変更します。

BACK INTO ENGLISH

kirb modifies him, making the movement of the legs, causing him to move forward rapidly to his geological position.

INTO JAPANESE

kirb は、彼、彼の地質学的位置に急速に前進する彼を引き起こして、足の動きを変更します。