Super hard mode, the worst mod of all.

[Spacestar TheThundersuncat]

Rogue males mate with pregnant ladies, the friendly neighbourhood bearyena, teens, males, clams and the seagrass, all resulting in the same untraceable notification. 

Walruus deer eat your creatures whole and leave only the skin behind. 

Meat eating plants now have a 7 tile radius and wander the island.

Food rots after two days.

All nests are replaced by dancing apendages every time it rains.

Dodomingoes get the respect they deserve and develop into winged rogue ladies. 

Rabbils steal the shape of your young and drain their lifeblood, replacing them with an infertile copy.

All berries are replaced by extra crunchy eyeballs, giving the "existntial despair" debuff (complete with a spelling error).

[Jojo]

By far the most terrifying is the meat eating plant one. A seven tile radius and they wander the island?! Gods help us.