You’d have to spend from a transaction that’s still in the mempool; while possible in theory, I don’t think any wallets currently support that.
I don’t see how you’d save any transaction costs. You cannot fill the mempool with a chain of transactions each spending the previous one’s output unless you pay increasing transaction fees. Otherwise that would constitute some sort of DoS attack where the network has to relay arbitrarily large amounts of data for only a negligible fee.