Elephant Grass

Oracle Text

Cumulative upkeep 1 (At the beginning of your upkeep, put an age counter on this permanent, then sacrifice it unless you pay its upkeep cost for each age counter on it.)

Black creatures can't attack you.

Nonblack creatures can't attack you unless their controller pays 2 for each creature he or she controls that's attacking you.

Card Rulings

2/1/2014 Unless some effect explicitly says otherwise, a creature that can't attack you can still attack a planeswalker you control.