Imam Ja’far Sadiq (a.s.) said:
“One day, the Holy Prophet (s.a.w.a.) wanted to attend
the Nature’s call [in a desert] while a person was also
present there.
His Eminence ordered two trees that grew there: “O trees come together.” They joined together at once.
The Prophet went behind the trees in private and then returned from there. That man went there, but did not find anything there. [Since the earth
had concealed it].
Behaarul Anwaar, vol. 16, p. 223
Isbaatul Wilayah (Part One) – Ayatullah AliNamazi Shahroodi (r.a.)