Berachot 33a: The snake-lizard vs. Rabbi Chanina ben Dosa

On Berachot 33a:

ת"ר מעשה במקום אחד שהיה ערוד והיה מזיק את הבריות באו והודיעו לו לר' חנינא בן דוסא אמר להם הראו לי את חורו הראוהו את חורו נתן עקבו על פי החור יצא ונשכו ומת אותו ערוד נטלו על כתפו והביאו לבית המדרש אמר להם ראו בני אין ערוד ממית אלא החטא ממית באותה שעה אמרו אוי לו לאדם שפגע בו ערוד ואוי לו לערוד שפגע בו ר' חנינא בן דוסא:

Or, in English:

Our Rabbis taught: In a certain place there was once a lizard⁷  which used to injure people. They came and told R. Hanina b. Dosa. He said to them: Show me its hole. They showed him its hole, and he put his heel over the hole, and the lizard came out and bit him, and it died. He put it on his shoulder and brought it to the Beth ha-Midrash and said to them: See, my sons, it is not the lizard that kills, it is sin that kills! On that occasion they said: Woe to the man whom a lizard meets, but woe to the lizard which R. Hanina b. Dosa meets!⁸

According to Soncino, this is the yarod, which is a hybrid between a snake and a lizard.

Caspian whipsnake

Steinsaltz writes: "Based on the descriptions in the Gemara, apparently the arvad is a type of snake or perhaps a large, very dangerous reptile. In parallel discussions in the Jerusalem Talmud, the arvad is called a chavarbar. Some identify this as the black snake or a snake of the coluber genus, which, although not poisonous, is very aggressive and bites."

Here is a collection of different versions of this story as it appears in different Rabbinic texts, in slightly different flavors. Read carefully and note the changes.

In the Tosefta:

and in the Yerushalmi, where it is havarbar rather than arvad: