Dozens of fantasy and isekai stories have the one-horn-rabbit as a staple beginner's monster.
Some examples:
- Re:Monster (day 4)
- I Said Make My Abilities Average! (ch. 19)
- Kenshi o Mezashite Nyūgaku Shitanoni Mahō Tekisei 9999 Nandesukedo!? (web novel ch. 22)
- Nidoume no Jinsei wo Isekai de (ch. 23)
- Saikyou no Shokugyou wa Yuusha demo Kenja demo naku Kanteishi (Kari) rashii desu yo? (ch. 2)
What is the origin of this monster, and why is it so common?