C-150 pilot reported engine failure during initial climb. Pilot made an immediate return to departure airport and landed.

Narrative

I was taking off from ZZZ from [Runway] XX. The RPM was fine on run up. The mag drop was appropriate. (75). There is no spark plug fowling; I had it leaned. There was no carb icing. Idle check was fine. I did a static RPM that was about 2450/60 (should be 2460 to 2560.) I started my takeoff roll. Everything was fine on the roll. I had the appropriate power; airspeed came alive. Rotation was normal. I was climbing out. I think I was about 500 and 600 feet. I was starting to think about turning for the noise abatement procedure on the departure as normal. About 500 or 600 feet; because I'd either just started or was about to start my turn; I noticed a decrease in RPM to about 2300. I called up on the radio ' I need to come back to land now' and started my turn back. I noticed I was about to stall; so I pushed the nose down and picked up enough speed that I was able to make it to Runway XY so I made that 500 foot 180 turn. I noticed a puff of smoke as I was turning back; from the left side of the engine. The propeller had stopped turning by the time I was down on the runway; and I just rolled off onto a taxi way; past the hold short. I think I even got landing clearance from ZZZ Tower. On ground; saw catastrophic explosion of crank shaft. Pieces of piston head found.