"Witch of the Black Forest" makes the Fusion Summon of this card even easier. You can fetch a "Thunder Dragon" with your "Witch of the Black Forest", use the effect of "Thunder Dragon" and Fusion Summon. A monster with 2800 ATK using a 1100 ATK monster.
It is possible, although highly unlikely that you will draw all the cards, to perform an OTK with this card and "Thunder Dragon". First, Fusion Summon this card with "Polymerization" and two "Thunder Dragons" (easily obtainable through "King of the Swamp"/"Fusion Sage"/"Synchro Fusionist" and the effect of "Thunder Dragon") and attack your opponent directly. Play "De-Fusion" and attack with the two "Thunder Dragons", then, finally, activate "Super Polymerization" for another attack with this card. As previously stated, this combo can be very tricky to pull off.