Sea Monsters! Leviathan and the Dragons

Illustration by Arthur Rackham
Or the praise of his martial exploits.-a (5) Who can uncover his outer garment?
Who can penetrate the folds of his jowls? (6) Who can pry open the doors of his face?
His bared teeth strike terror. (7) His protective scales are his pride,
Locked with a binding seal. (8) One scale touches the other;
Not even a breath can enter between them. (9) Each clings to each;
They are interlocked so they cannot be parted. (10) His sneezings flash lightning,
And his eyes are like the glimmerings of dawn. (11) Firebrands stream from his mouth;
Fiery sparks escape. (12) Out of his nostrils comes smoke
As from a steaming, boiling cauldron. (13) His breath ignites coals;
Flames blaze from his mouth. (14) Strength resides in his neck;
Power leaps before him.
Demons! Sheydim and Mazzakin

Illustration from Jewish Fairy Tales and Legends (1919) by Aunt Naomi (aka Gertrude Landa) https://www.sacred-texts.com/jud/jftl/jftl00.htm
The crowding at the kalla, the gatherings for Torah study during Elul and Adar, is from the demons;
those knees that are fatigued even though one did not exert himself is from the demons;
those clothes of the Sages that wear out, despite the fact that they do not engage in physical labor, is from friction with the demons;
those feet that are in pain is from the demons. One who seeks to know that the demons exist should place fine ashes around his bed, and in the morning the demons’ footprints appear like chickens’ footprints, in the ash. One who seeks to see them should take the afterbirth of a firstborn female black cat, born to a firstborn female black cat, burn it in the fire, grind it and place it in his eyes, and he will see them. He must then place the ashes in an iron tube sealed with an iron seal [gushpanka] lest the demons steal it from him, and then seal the opening so he will not be harmed. Rav Beivai bar Abaye performed this procedure, saw the demons, and was harmed. The Sages prayed for mercy on his behalf and he was healed.

Giants!

Illustration from Jewish Fairy Tales and Legends (1919) by Aunt Naomi (aka Gertrude Landa)
(ד) הַנְּפִלִ֞ים הָי֣וּ בָאָרֶץ֮ בַּיָּמִ֣ים הָהֵם֒ וְגַ֣ם אַֽחֲרֵי־כֵ֗ן אֲשֶׁ֨ר יָבֹ֜אוּ בְּנֵ֤י הָֽאֱלֹהִים֙ אֶל־בְּנ֣וֹת הָֽאָדָ֔ם וְיָלְד֖וּ לָהֶ֑ם הֵ֧מָּה הַגִּבֹּרִ֛ים אֲשֶׁ֥ר מֵעוֹלָ֖ם אַנְשֵׁ֥י הַשֵּֽׁם׃
(4) The Nephilim were in the earth in those days, and also after that, when the sons of nobles came in unto the daughters of men, and they bore children to them; the same were the mighty men that were of old, the men of renown.
Estries!

"The Witches Pool" by Arthur Rackham
Siman 1465
There are women called estries, mares or werewolves. They were created at twilight (bein ha-shemashot). They could perform a certain act and thereby change form. There was one woman who was an estrie and she was very sick. Two women were with her at night; one was sleeping and one was awake. And the sick woman stood up beside [the sleeping woman] and shook out her hair and tried to fly and tried to suck the blood of the sleeping woman. And the woman who was awake screamed and woke her friend and they grabbed the sick estrie, and after this she slept. And if she had been able to attack and kill the other woman, then the estrie would have lived. But since she was not able to attack the other woman, the estrie died, because one that issues from blood needs to drink the blood of living flesh. The same is true of the werewolf. And since the mare and the estrie need to shake out their hair before they fly, one must cause her to swear to come with her hair shaken out, so that she cannot go anywhere without his permission. And if one strikes an estrie or if one sees her, she cannot live, unless she eats of the bread and salt of the one who struck her. Similarly, if she attacks someone, he must eat from her bread and salt. Then the soul will return to the way it was before.
Siman 1466
There was a [non-Jewish] woman who was suspected of being an estrie, and she would attack [people]. She appeared to a Jew as a cat and he hit her. The next day she asked him to give her some of his bread and salt, and he wanted to give it to her. An old man said to him “Be not overly righteous” (Ecc. 7:16). Where one has an obligation to others, one must not exhibit excessive piety, for if she lives, she will harm people. Thus the Holy One, blessed be He, created her for you [as a test], just as he created Amalek for Saul and punished him for letting him live.
MS Oxford 1567, 41b
Know too that there was a witch, an estrie, who once was caught by a man. He said to her, Do not [try to] escape from my grasp, as you have caused numerous deaths in the world. What can I do to you so that after your death you will not consume [people’s flesh]? She said to him, If you find [an estrie] in the grave with her mouth open, there is no remedy, for her spirit will attack the living. And there is no remedy unless a spike is hammered into her mouth and into the earth. Then she will attack no more. And for this reason, one should fill her mouth with stones.
Translations of Sefer Hasidim by Eli Clark from Torah Musings "Vampires and Witches in Sefer Hasidim" https://www.torahmusings.com/2011/10/vampires-and-witches-in-sefer-hasidim/