Gouache Ghouls is the third stage in Grotesque Gallery.
The level begins by spawning an Angel Fanboy and an Angelic Gory. When the base reaches 99% health, then all of the other enemies will spawn infinitely. Try all you want, but you will never beat this buffed bunch of Angels.
However, there is a twist: If you stall the initial Angelic Gory for 66.67 seconds2000f, infinite Ms. Signs will spawn, allowing you to push them back and destroy the base.
Since the stage has a maximum number of 10 enemies, stall for about three minutes with manic erasers until 10 Ms Signs come out, they will be knocked behind the tower and you can finish the stage without the other angels appearing.
- Eye of the Storm, Crazed Tank Cat, Eraser Cat, Crazed Cow Cat and Awakened Bahamut.
Demonstrated video: 
Strategy 2 (Feat. Prof. Cat Jobs)
Row 1: Banner Cat, Angry Delinquent Cat, Wrestling Cat (Weaken UP Sm), Dark Cat, Dark Lazer (Weaken UP M)
Row 2: Prof. Cat Jobs, C. Cow Cat, A. Bahamut
When the Angelic Gory is at the Base, spawn Cat Jobs. Thanks to the Combos, he will Perma-Weaken Angelic Gory so he deals only very, very little Damage. When the 8 Ms Sighs Appear, Kill the Angelic Gory with Bahamut and spawn a Crazed Cow. It deals very little Damage Per Hit, so it won't kill the Ms. Signs and push them behind the Base. A. Bahamut will destroy the Base, and that's it.
Strategy 3 (cheese) featuring Warlock and Pierre
This stage becomes extremely easy if you have Warlock and Pierre. Since there are no boss waves and the base has only 250k health, Warlock and Pierre - if properly leveled - can one-shot the base without summoning Sunfish Jones or Sleipnir. If this stage had a boss wave, the base would be left with 1 HP, forcing you to fight the aforementioned enemies.
- The Sunfish Jones encountered in this level has the highest health of any enemy with any magnification in this game, which is 12,000,000 HP. (Credits to SomeRandomGiantUser)
- However, without the Cats of the Cosmos Mystery Treasure, Cat God will trump this health, having 15,000,000 HP.
- Also, with no anti-alien treasures, Cli-One from Close Encounters has even more health than that, having 16,000,000 HP and as such has the highest HP of any enemy in the game.
- Those impossible enemies are actually beatable, but this requires a huge amount of skills and very strong cats. Also, if you wish to fight them and stand a chance, you need to wait for exactly 7 Ms. Signs to spawn before hitting the enemy base if you want to take the challenge in killing the 1000% Sunfish.(Credits to Chillhola)