Tu's Terrific Talon

You evoke a small knife made of a blackened metal in your free hand. The blade is similar in size and shape to a dagger, and it lasts for the duration. If you let go of the blade, it disappears, but you can evoke the blade again as a bonus action.

You can use your action to make a melee spell attack with the knife, which on a hit deals 1d4 necrotic damage

As an action, you can stab a creature and cause the blade to explode. The target must make a constitution saving throw or take 2d6 necrotic damage

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the damage increases by 1d4 and 1d6 for every two slot levels above 2nd.