Ribbitius, The Frog King

All frog creatures have +2/+2

Frog creatures are indestructible when blocking, if a
card named Castle Frog is on the battlefield.

- "In the citadel of Castle Frog, no threat may breach
those walls. The halls are armed with sorcerers, the
king's men, and an army the size of an entire pond."

—Xerdle, Bishop of the Bog