What does Cassius compare Caesar to?

In act one, scene two, Cassius attempts to persuade Brutus into joining the conspirators to assassinate Julius Caesar. Cassius tells Brutus that the Romans have essentially turned Caesar into a god and compares Caesar to the Colossus of Rhodes by saying:

"Why, man, he doth bestride the narrow world Like a Colossus, and we petty men walk under his huge legs and peep about to find ourselves dishonorable graves" (Shakespeare, 136-140).

The Colossus of Rhodes was a giant statue of the Greek sun-god Helios and is considered one of the Seven Wonders of the Ancient World. By comparing Julius Caesar to the revered, magnificent statue, Cassius emphasizes Ceasar's popularity and elevated status. Brutus is intrigued by Cassius' moving arguments and is unaware of Cassius' true intentions.
In the following scene, a terrible storm rages on the night before the Ides of March. Thunder and lightening foreshadow Caesar's brutal assassination and Casca runs into Cassius, who dares the lightning to strike him. Cassius proceeds to compare Julius Caesar to the "dreadful night" by telling Casca:

"Now could I, Casca, name to thee a man [Julius Caesar] most like this dreadful night, that thunders, lightens, opens graves, and roars as doth the lion in the capitol-" (Shakespeare, 73-76).

Overall, Cassius compares Julius Caesar to the Colossus of Rhodes and to the stormy night in act one. Cassius' comparisons portray Julius Caesar as a revered, malevolent man.

Cassius compares Julius Caesar to Colossus.
In act 1, scene 2, a scene that is sometimes called "the seduction scene," Cassius tries to convince Brutus that Caesar has become despotic:

doth bestride the narrow worldLike a Colossus, and we petty menWalk under his huge legs and peepaboutTo find ourselves dishonorable graves. (1.2.141-143)

As Cassius continues, he asks why Caesar's name should be spoken as though it were announced with trumpets. He tells Brutus that the name of Brutus is "as fair a name" and should also be said with trumpets blowing. Besides this arrogance of Caesar's, Cassius suggests to Brutus that Rome should not be ruled by just one man. After Caesar has killed Pompey, Cassius is worried that he has become "like a god," and if he is made the single ruler of Rome, Caesar will become despotic. He points out that there was another Brutus who helped expel the last King of Rome. Having listened to Cassius, Brutus promises to consider what Cassius has said.