The Mystery Cave is a theme in Angry Birds: 4 which contains 8 levels on 2 sets.
Levels
Set 1
Theme 19-1 (start) Birds: Navy Bird 10x, Pigs: Small Pig 4x, Medium Pig 6x
Theme 19-2 Birds: Navy Bird 3x, Pink Bird 7x, Pigs: Small Pig 9x, King Pig
Theme 19-3 Birds: Navy Bird 3x, Pigs: Medium Pig 10x
Theme 19-4 Birds: Navy Bird 6x, Pink Bird 2x, Teal Bird and Purple Bird, Pigs: Cardboard Cutout 9x, King Pig
Theme 19-5 Birds: Boomerang Bird 5x, Fake Orange Bird 3x and Teal Bird 2x, Pigs: Warp Pig 2x, Medium Pig 8x
Theme 19-6 Birds: Bounce Bird 8x, Tornado Bird and Teal Bird, Pigs: Warp Pig 10x >[HARDEST!]<
Theme 19-7 Birds: Teal Bird Caged, Big Brother Bird 10x, Pigs: Warp Pig 1x, Medium Pig 9x
Theme 19-8 (First appearance of Teal Bird) Birds: Teal Bird 10x, Pigs: Helmet Pig 7x, Medium Pig 2x, King Pig
Set 2
Theme 20-1 Birds: Platinum Bird 8x, Real Orange Bird 2x, Pigs: Helmet Pig 10x
Theme 20-2 (First appearance of the Plated Bird) Birds: Plated Bird 10x, Pigs: Warp Pig 2x, Helmet Pig, Medium Pig 7x
Theme 20-3 Birds: Plated Bird 3x, Teal Bird 3x, Real Orange Bird 2x, Big Brother Bird 2x, Pigs: Cardboard Cutout 7x, King Pig, Helmet Pig 2x
Theme 20-4 (First appearance of the Idiot Bird) Birds: Idiot Bird 10x, Pigs: Small Pig 9x, Large Pig (Idiot Bird has reversed controls forever unless it is not yet used)
Theme 20-5 Birds: Navy Bird 8x, Idiot Bird 2x, Pigs: Cardboard Cutout 8x, King Pig, Helmet Pig (Eggs are found here)
Theme 20-6 Birds: Idiot Bird 8x, Navy Bird 2x, Pigs: Carboard Cutout, King Pig, Helmet Pig 8x
Theme 20-7 (First appearance of the Lame Bird) Birds: Lame Bird 10x, Pigs: Warp Pig, Helmet Pig 9x
Theme 20-8 (First appearance of the Ghost Bird) Birds: Ghost Bird 9x, Platinum Bird, Pigs: King Pig, Cardboard Cutout, Helmet Pig, Small Pig 3x, Medium Pig 4x
