They feature her daughter Kynadee, five - in full zombie makeup - clutching either a spooky doll or a blood-covered "brain".
Just as grim is her little brother, 10-month-old Kamden, pictured soaking in a metal tub filled with fake blood.
Red fluid drizzles down his face into his mouth while he feasts on the brain, held in his blood-soaked hands.
Bobbi, a part-time photographer, snapped the duo at a local lake, and in the family's garden in Oklahoma, US.
Aiming to show some seasonal fun in the run-up to Halloween, she shared the images on Facebook.
But, some people immediately posted their grave concerns as her over-the-top shots went viral and were shared more than 200,000 times.
Internet trolls claimed that her children were unsafe and should be taken away from her.
Some also criticised the lashings of blood and brains, saying it looked like an "abortion scene".
Bobbi tried to explain that her pics were "something fun for the kids for Halloween".
She said: "I was originally going to do a milk bath with pumpkins for fall, but I thought I would try this instead.
“I do want to convey that my children are very, very well taken care of. This was just for fun.
"Many people have said that my children should be taken from me and I know that is not true. My kids are the most important things in my life and they are always happy and healthy.
“I would also like to add that these were very quick shoots. My son was in that bucket for maybe 10 minutes tops."
The only problems I had to overcome during the shoots was the clean-up!
Bobbi Rylant, Mum
Bobbi said the gory photos were created with food: "The stuff on [Kamden's] head is just strawberry and chocolate syrup mixed together and the brain is just a prop from a local Halloween store."
The tub contained water mixed with a cherry soda drink.
She was a bit worried while taking photos of Kynadee at the lake, though, as her daughter got a splinter in her foot and started crying.
Bobbi said: "I was hoping no one would think I was hurting her since she looked all bloody and was screaming!"
The only real horror was cleaning the gunge up afterwards.
