Selkie Hedge-Mage

Pay one green-or-blue pip on top of the generic cost, and this Merfolk slots into a mono-green deck, a mono-blue deck, or a true Simic build with equal comfort: each pays exactly what it wants and strands nothing. That hybrid split gives the card three distinct audiences, and it sits at the center of a small cycle of land-type-keyed creatures cut along the same lines. The two entry triggers tax that flexibility by counting permanents with the right subtypes: two Forests turn it into three points of incidental lifegain, two Islands let it bounce a tapped creature for tempo, and only a deck running both subtypes collects both at once. The check is on the Forest and Island subtypes rather than basics, so a dual like Breeding Pool feeds both halves on a single permanent. The bounce is fenced off deliberately, since the target must already be tapped: that narrowing keeps it from clearing untapped blockers and pins its value to an opponent's tapped attackers or activated creatures. This is the familiar shape of designs that scaled with how committed your manabase was: maximally splittable when you needed a single color, rewarding when you could afford both. But the bargain has teeth. Both triggers are gated on those land counts, so a build that meets neither threshold gets a 2/2 whose abilities sit on the card and never fire: the body is the price you pay when your colors do not line up.