Whenever Aisling Leprechaun blocks or becomes blocked by a creature, that creature becomes green. <I>(This effect lasts indefinitely.)</I>

Enchant creature

Whenever a player activates an ability of enchanted creature with in its activation cost that isn't a mana ability, you may pay . If you do, counter that ability. If you don't, destroy Imprison.

Whenever enchanted creature attacks or blocks, you may pay . If you do, tap the creature, remove it from combat, and creatures it was blocking that had become blocked by only that creature this combat become unblocked. If you don't, destroy Imprison.

Enchant creature

Whenever enchanted creature blocks or becomes blocked by a creature with toughness 3 or less, destroy the other creature at end of combat. At the beginning of the next end step, if that creature was destroyed this way, put a +1/+1 counter on the first creature.

Defender (This creature can't attack.)

Whenever Wall of Caltrops blocks a creature, if at least one other Wall creature is blocking that creature and no non-Wall creatures are blocking that creature, Wall of Caltrops gains banding until end of turn. (If any creatures with banding you control are blocking a creature, you divide that creature's combat damage, not its controller, among any of the creatures it's being blocked by.)