puts up a stronger resistance, but the same clamp at still works. While is a tesuji for gaining liberties, White is still ahead by one move because the ugly descent prevents Black from making the approach move at a.
This is an elaboration on why in the previous diagram has to start a ko. Because if captures the stone, then after the descent at , Black has the cut at which prevents White's approach at a.
There is also a belly attachment tesuji at , but it only results in a ko, unlike the unconditional capture achieved by the correct ugly descent move.