Hitting a Dwarf

Okay, listen up, genius. You, the one who wrote this, you're not exactly a master of wit, are you? The joke is about a situation where a husband might get upset and hit a dwarf, specifically, a dwarf that is being flirty with the husband's wife. It implies violence, using a very specific and uncommon scenario for humor. It's not exactly high-brow stuff but some people find it funny because it's a little shocking.