sources mekorot - Animal R'aim of the midrash

I saw in the book, "The midrash says" by Rabbi Moshe Weissman that the Midrash Socher Tov 22 explains that a creature called R'aim that David mistook as a hill, lifted David up into the sky and only after seeing the lion did it crouch down and David managed to jump off and escape (see here for details).

What is this animal R'aim?

Answer

See Gittin 68b where Shlomo Hamelech is talking to Athmedius King of Sheidim:

כתיב (במדבר כד, ח) כתועפות ראם לו ואמרינן כתועפות אלו מלאכי השרת ראם אלו השדים מאי רבותייכו מינן א"ל שקול שושילתא מינאי והב לי עיזקתך ואחוי לך רבותאי שקליה לשושילתא מיניה ויהיב ליה עיזקתיה בלעיה אותביה לחד גפיה ברקיעא ולחד גפיה בארעא פתקיה ארבע מאה פרסי על ההיא שעתא אמר שלמה (קהלת א, ג) מה יתרון לאדם בכל עמלו שיעמול תחת השמש (קהלת ב, י) וזה היה חלקי מכל עמלי

[Loose translation:] Shlomo Hamelech said to Athmedius: "It is written that "to [God], they are like Toafos R'eim". Toafos are the ministering angels. R'eim is the Sheidim (loosely translated as demons). Shlomo asked: "[I understand that angels are great. But] Sheidim, in what way are you greater than us [humans]?"
Athmedius resonded: "let me free from my chains and give me your ring and I will show you my greatness [of the R'eim]".
So Shlomo let him free from his chains and handed him his ring. Athmedius swallowed Shlomo [alive], stretched one wing out to heaven and one down to Earth (astronomical proportions) and spat him out 400 pharsangs (about 1600km) away. And then Shlomo [was ousted from his throne and was left with just the clothes on his back and] proclaimed: "What does one gain in all his labour under the sun?" "And this was my portion from all my hard work."

• Sheidim have massive proportions as the Gemora mentions earlier 68a מטא דיקלא חף ביה שדייה מטא לביתא שדייה - that any palm tree or house that Athmedius brushed collapsed due to his large proportions


• Sheidim could disguise themselves as a hill after all did Athmedius not disguise himself as Shlomo haMelech himself (Gittin 68a). They can also fly as indicated aboveAthmedius had wings.


• Sheidim also have horns as the Gemora in Sotah 48a says about the Sheid that destroys deserted homes: (ישעיהו כד, יב) ושאיה יוכת שער אמר מר בר רב אשי לדידי חזי ליה ומנגח כי תורא - Mar Bar Rav Ashi said "I saw that Sheid (see rashi) and it gores like an ox" i.e it has horns which it gores with.


• And if you're wondering: Why did the Sheid crouch down in fear when he saw the lion if even a human can kill a lion? This was asked by Caesar to Rabbi Yehoshua in Chullin 59b and Rabbi Yehoshua responded that there is a certain אריא דבי עילאי - Lion of upper realms that when it roared 400 pharsangs (1600km) distance away from Rome, all the pregnant women miscarried and the walls of Rome collapsed even a sheid would be afraid as Amos 3,8 states: “The lion has roared, who will not fear?”.