Ekadasha Rudra mantra is a set of eleven different mantras. During Maha Shivaratri or Maha Rudra Yagnya, all of the eleven mantras, if recited, are very beneficial for people.
Kapali
Om HumHum Satrustambhanaya Hum Hum Om Phat
Pingala
Om Shrim Hrim Shrim Sarva Mangalaya Pingalaya Om Namah
Bhima
Om Aim Aim Mano Vanchita Siddhaya Aim Aim Om
Virupaksha
Om Rudraya Roganashaya Agacha Cha Ram Om Namah
Vilohita
Om Shrim Hrim Sam Sam Hrim Shrim Shankarshanaya Om
Shastha
Om Hrim Hrim Safalyayai Siddhaye Om Namah
Ajapada
Om Shrim Bam Sough Balavardhanaya Baleshwaraya Rudraya Phut Om
Ahirbhudanya
Om Hram Hrim Hum Samastha Graha Dosha Vinashaya Om
Sambhu
Om Gam Hluam Shroum Glaum Gam Om Namah
Chanda
Om Chum Chandishwaraya Tejasyaya Chum Om Phut
Bhava
Om Bhavod Bhava Sambhavaya Ishta Darshana Om Sam Om Namaha