When we talk about deceptively difficult exercises then the Foam Rolling Plank definitely springs to mind. The instability created by the foam roller adds perturbations, as does it's slower and controlled rolling upwards and downwards. This is a huge test for the abdominal muscles to control lumbar extension, so should be built towards.
Do not drop an imaginary drink balancing on your lower back
Push your feet into the floor, keeping your knees straight
Do not link your hands together
Targeted muscles trained
Key movements trained
Hip anterior stability
There is a high shoulder stability challenge to this exercise and therefore the rotator cuff may be extremely challenged towards the relative end of your movement. The same can be said of your latissimus doors and pectorals major sternal fibres.
There is a very large lumbar anti-extension challenge in this exercise, if you are feeling it in your lower back either during or after the exercise then it's likely that this is too advanced for you and you should regress to an easier exercise and build from there.
Keeping the ankle stiff and pushing the feet into the floor may work the hip and abdominals harder, in which case you may want to reduce the range of motions your shoulders go through to accommodate the exercise.