Squishy Hollows is the fourth stage in Risqué Terrain.
1,200f (40 seconds) after the battle begins, 3 Duches appear, each separated by 10f (0.33 seconds) between Duche. Dagshund appears 60f (2 seconds) after the 3rd Duche. The Duches and Dagshund respawn infinitely every 1,600f (53.33 seconds).
This level is fairly simple, spamming meatshields while stacking Dragon Cat and Sexy Legs Cat to accumulate ranged DPS. You can also use UFO Cat for the Duches, but since Dagshund will easily kill it, you shouldn't really rely on it. If you can't do this stage, go back to EoC to grind treasures and fortify your army.