Maybe get an ab roller or wheel if you don’t have a suitable piece of furniture.
Or just hold up your legs so that your thighs are perpendicular to the floor and your lower legs parallel. Fold your arms across your chest, and touch your elbows to your thighs.
Once your shoulder blades are off the floor, your abs are as contracted as they are going to get. The rest of the movement is hip flexors and the abs are acting as stabilizers.
And/or do planks.
Regards,
Shodan
I was answering for the OP, whom I don’t believe has superpowers.
BTW, feet on the ceiling are reserved for smoochy time with MJ. 