The ornamental design for a hookahbowl, as shown and described.
FIG. 1 is a front elevation view of a hookah bowl, embodying my new design;
FIG. 2 is a top plan view thereof;
FIG. 3 is a bottom plan view thereof;
FIG. 4 is a top perspective view thereof; and,
FIG. 5 is a bottom perspective view thereof.
The hookah bowl is understood to be radially symmetric.
The dot-dot-dash broken lines shown are included for the purpose of illustrating the unclaimed circular portions inside the bowl and form no part of the claim.