Fling your creature, deal some damage! Here Top Swap is used as a way to be like, "Yeah buddy, there's more where that came from!" Because of the nature of needing to sacrifice creatures in order to fling, this is gated partly on having other things to sac.

There's a few differences between this and Fling. The Top Swap mechanic filters, so it should definitely not just be Fling with upside. It also maybe doesn't want to hit "any target"? Being able to just, abyss your opponents is annoying to deal with. So this version hits only face... though maybe it should also hit Planeswalkers, I'll go edit that in.

It's also a Sorcery! Does this seem like it'd be safe at Instant? "Turn three I hit you with my hasty creatures; on your end step I fling one at you; on turn four I hit you with my hasty creatures, thing fling." That play pattern needs to make sure it doesn't dominate too much. We also don't want to have this just blank removal by being a reusable Fling every turn.