“what nasty evil stupid thing has Cruz done or said?”
Evil: Lied and stole votes from Carson.
Evil: Lied and said Trump stole a house from a little old lady and bulldozed it.
Stupid: Said, “I believed Mitch McConnell”.
Nasty: Broadcasted to Iowans their neighbors’ voting history.
... for a start
You left out: Lied and first said it was Trump’s campaign who spread the Carson campaign suspension rumor. Luckily, folks saved screenshots of all of the CRuz team/Carson fibs.