Charix, the Raging Isle 
Legendary Creature — Leviathan Crab
Spells your opponents cast that target Charix cost more to cast.
: Charix gets +X/-X until end of turn, where X is the number of Islands you control.
Legality
standardNOT LEGALpioneerLEGALmodernLEGALlegacyLEGALvintageLEGALcommanderLEGAL