“like” needs an object for the comparison. Something can’t just “look like”, it has to look like something. “What” is an indirect reference to an object so you can say what it looks like.
“How” is a reference to an adjective or a description, so it doesn’t need another word to make it a comparison. How does the cave look? It looks terrifying.
Yeah cos it’s real lucky when you’re not paying attention and light the filter end