When describing how Hadhrat Shaykh al-Hadith Mawlana Muhammad Zakariyya (may Allah enlighten his grave) performed his nafl (optional) salah (ritual prayer) , Hadhrat Mawlana Yusuf Motala (may Allah protect him) writes:

Hadhrat would be performing optional salah in the courtyard of the Mosque. He performed this in the heat of the sun from  Ishraaq (sometime after daybreak) to just before noon. The Salah would be of such devotion and concentration, that on numerous occasions  flies were seen resting on his neck and his cheek just as honeybees rest on a honeycomb. The flies would be in such number, that his skin would be covered and could not be seen. Inspite of this, he would not make the slightest movement. However, sometimes in the state of ecstasy, his right shoulder would shake with great speed and strength.

Hadhrat Shaikhul-Hadeeth Moulana Muhammad Zakaria rahmatullahi alaihi) & I, Page 7 (Jamea Publication No. 27) [The translation reproduced above has been edited by the blog administrator]