What punctuation mark can sometimes be used by itself instead of using a comma plus the word and?

The punctuation mark that can sometimes be used by itself instead of a comma plus "and" is the semicolon (;).

Here's an example:

* With a comma and "and": The dog barked loudly, and the cat hissed.

* With a semicolon: The dog barked loudly; the cat hissed.

The semicolon is used to join two closely related independent clauses. It indicates a stronger connection than a comma, but a weaker connection than a period.