Upon hitting the block from the left or right with the scythe, Specter Knight will be bounced back, opposite to the direction he is facing. If Specter Knight jumps on the block, he will be bounced upwards in the same fashion as if one jumps on Goo. Doing either of these actions will immediately break the block afterwards.
They will occasionally appear to have a Birder trapped inside, as pictured above. If this is the case, if the block is broken in any way, it will release the Birder.