My submissions are a multiplying Thorn Bush and a teleporting Mana Cactus. Thorn bush satisfies the minion challenge and Cactus satisfies the magic trigger challenge.

This minion slowly multiplies around the board, creating an obstacle for path units, giving cover for short-range units, and threatening enemy minions. Using this minion would call for using more unblockable and magic units to get around the bushes more easily.

The Mana Cactus has the same concept of poisoning on contact. It can teleport near key squares and threaten enemies with a poison trigger at a low point cost. It also poisons melee attackers, making it a bit harder to get rid of.