Bits for plunge cutting usually have an extra cutter on the end for "drilling" down into the workpiece as you plunge. These bits include straight bits, plunge round-over bits, etc. The extra cutter is needed so that the bit can remove the material beneath it as it enters the wood.
If you want to put a detail in the middle of a board, you can use a plunge straight cutter first to make a clearance cut, then use a regular bearing profile bit with the bearing removed.
If you want to put a detail in the middle of a board, you can use a plunge straight cutter first to make a clearance cut, then use a regular bearing profile bit with the bearing removed.
