to have a voracious desire for / to covet / greedy / corrupt
贪
=
今
+
贝
:
The crab (贝) is so greedy (贪) that it rented out its shell to Tecumseh (t) to live in in front of the anthill (an1). It can't wait for the first day of the month to appear on its rip-off calendar (今) so that it can go to collect the rent.