Manias Vernum's Stone

Theme: Vernum used this stone to create his favorite creatures, rodents. However, because of the origin of the stone, it would only effect liquids, so it created rodents made out of nearby liquid.
Activation:
Vernum's Call:This rune can be used to create a singular rodent out of a quart of liquid, the creature will then understand a phrase command you tell it, and fulfill it. You may suffer 1 strain as an action to sense through it instead of yourself. You lose your connection, senses and command, over the creature after 5 minutes.
Implement:
Vernum's Allegiance: You may add Additional Target without increasing the difficulty when casting spells (Flavour to somehow include liquid rodents). Attack spell cast with this increase their base damage by three.