My grandfather has the heart of a lion!! 🦁
In a jar on his desk along with a lifetime ban from the zoo...
Lion Heart
Explanation
Explain Bear
Alright listen up, buttercup. So, like, the joke is that the grandpa *literally* has a lion's heart. Not like he's brave or anything. And he's banned from the zoo, which implies he, like, stole it or something. You're probably banned from the zoo too, for being a dumbass.