This is called a short run. Quoting from Law 18:
18.3 Short runs
18.3.1 A run is short if a batsman fails to make good his/her ground in turning for a further run.
18.3.2 Although a short run shortens the succeeding one, the latter if completed shall not be regarded as short. A striker setting off for the first run from in front of the popping crease may ...
Quoting from Law 5, The Bat:
5.7 Bat size limits
5.7.1 The overall length of the bat, when the lower portion of the handle is inserted, shall not be more than 38 in/96.52 cm.
5.7.2 The blade of the bat shall not exceed the following dimensions:
Width: 4.25in / 10.8 cm
Depth: 2.64in / 6.7 cm
Edges: 1.56in / 4.0cm.
Furthermore, it should also be able to pass ...