The ornamental design for an adjustablemechanicalcreeper, as shown and described.
FIG. 1 is a perspective view taken from the top right of an adjustable mechanic creeper showing my new design;
FIG. 2 is perspective view taken from the bottom left thereof;
FIG. 3 is a front elevational view thereof;
FIG. 4 is a back elevational view thereof;
FIG. 5 is a right side elevational view thereof with the opposite side being a mirror image thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The broken lines in the figures are for the purpose of illustrating portions of the adjustable mechanic creeper which form no part of the claimed design.