The hungry tiger jataka is my favorite
"One day, the Bodhisattva and one of his disciples decided to take a stroll in the forest nearby. This had become a regular practice. They often went for strolls.
While they were walking, the Bodhisattva notices something extremely terrifying. He saw a tigress, which looked weak and hungry. The tigress was about to devour her own cubs. Now, that moved the Bodhisattva’s heart. He did not want the poor animal to suffer the guilt of eating her own cubs. So, he came up with an idea.
He sent his disciple back to do something. The Bodhisattva had decided that he would offer himself as food to the starving tigress. He simply could not let her eat her cubs. And he knew if his disciple had seen this, he would definitely stop the Bodhisattva from offering himself. You may also like to read, The Tiger And The Golden Bangle.
After the disciple is gone, the Bodhisattva approached the tigress. With the utmost compassion in his heart and no malice, he let the tigress devour him. The tigress ate him and fed the cubs as well. After a while, the disciple returned. When he saw the Bodhisattva’s blood stained clothes, he realized what had happened.
He knew the Bodhisattva well. So, he knew the hermit had offered himself to save the tigress. He went back and told his fellow disciples of the Bodhisattva’s sacrifice out of love and compassion. "
Plain Buddhism was kind of a downer so they made stuff like pure land buddhism that is more of a fun afterlife version instead of hardcore OG Buddha which is like kill yourself and stop existing forever because the world is just an eternal cycle of pain and reincarnation into more pain forever.