Rasool (s) foretold about Muwaiyah's deviance.

http://www.usc.edu/dept/MSA/fundamentals/hadithsunnah/bukhari/052.sbt.html#004.052.067

Volume 4, Book 52, Number 67:
Narrated 'Ikrima:
that Ibn 'Abbas told him and 'Ali bin 'Abdullah to go to Abu Said and listen to some of his narrations; So they both went (and saw) Abu Said and his brother irrigating a garden belonging to them. When he saw them, he came up to them and sat down with his legs drawn up and wrapped in his garment and said, "(During the construction of the mosque of the Prophet) we carried the adobe of the mosque, one brick at a time while 'Ammar used to carry two at a time. The Prophet passed by 'Ammar and removed the dust off his head and said, "May Allah be merciful to 'Ammar. He will be killed by a rebellious aggressive group. 'Ammar will invite them to (obey) Allah and they will invite him to the (Hell) fire."

Note : Ammar (RA) was killed and beheaded during the battle of Siffin, when Muwaiyah fought against Imam Ali (as). Ammar (RA) was martyred by Muwaiyah's 'camp'.

In the Battle of Siffin, when the head of Ammar Yasir (RA) was cut off and was taken to Muawiyah, two people were arguing over it, each one claiming that he had killed Ammar.

Sunni references:
- Musnad Ahmad Ibn Hanbal, Traditions #6538, #6929 Printed in Dar al- Maarif, Egypt 1952
- al-Tabaqat, by Ibn Sa'd, v3, p253