Which of these should I write?

So, I guess you've inspired me, so I'm going to give writing another shot. The only problem is I have two ideas that are about equally good in my opinion. I assume if I finish the first I'll write them both, but which one of these should I focus on first?

A) The lighter of the two, involving two endlessly reincarnating buddies. They can create their bodies every time they're reborn. They are part of a large number of reincarnating guys. Usually they'll go for a human of some kind or a relatively mundane animal, sometimes they'll make something crazy but those damn humans keep shooting those ones before they have the chance to do anything. Anyway, in one of their earlier incarnations, the buddy who isn't the main character (he's the second main character) falls in love with a (French) Canadian Lynx, for all of half an hour before she dies. He doesn't know if she's going to be reborn or not (it never came up, he says), but he's convinced she will. So they both have hilarious misadventures for the next few thousand years, while endlessly searching for the girl. The main character is just along for the ride.

B) Far and away the darker one, it struck me that in basically all of the Fantasy books I've ever read, the heroes all go into some cave/dungeon/what have you after a magical Macguffin or something. The dungeons are usually quite large, potentially holding enough Macguffins to go around, but never have I ever read about two or more groups of protagonists unrelatedly exploring the same dungeon at the same time. So I ran with this, and came up with this idea. Say there's roughly 15 individuals all searching one dungeon for different reasons. Some of them came together, some alone, but they're all different, and hence, there can be good character interaction for all. For example: typical street rat thief guy is prowling along, and notices the cute ditz that really has no clue what she's doing because she's young and naive is about to open a trapped door that can potentially kill her. What does our favorite rogue do? Like, does he tell her not to open it, does he disarm it for her, does he do nothing? I think this story could be way interesting, if I did it right.

So there you have it. In the end, I'll probably write both of these, but in the meantime, which should I focus on first? YOU DECIDE!

You should write whatever you most feel like writing, of course.

(But for whatever it's worth, I find the second idea really intriguing.)

Man, if I knew which one of these I'd rather write, I wouldn't be asking for advice!

I'd say either write out some notes for both or just write out a proto-chapter for both.

See how well you can work with one compared to another.

I like the first one; the second one reminds me of the Maze of the Many from Goblins (not in a copycat way, just in a thematically similar way).

In a good way?

P.S. Thanks for referencing Goblins, I'd never heard of it but was looking for a good new comic to read, ever since I caught up to Oot S. Twice.