Nicejob, I liked it, but you have some errors, like:
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(Unit-type of (Triggering unit)) Equal to Slytherin Student
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(Unit-type of (Triggering unit)) Equal to Slytherin Student
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(Unit-type of (Triggering unit)) Equal to Slytherin Student
that can never be true, change it to:
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Or - Conditions
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(Unit-type of (Triggering unit)) Equal to Slytherin Student
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(Unit-type of (Triggering unit)) Equal to Slytherin Student
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(Unit-type of (Triggering unit)) Equal to Slytherin Student
Also, there are many spells that the SpellTester doesn't have.
In Expelliarmus, I don't think
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Unit - Set level of Dummy Ability for (Last created unit) to (Level of Colloportus for (Triggering unit))
Was what you wanted, but
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Unit - Set level of Dummy Ability for (Last created unit) to (Level of Expelliarmus for (Triggering unit))
Once, I was disarmed, picked up my wand, and remained silenced. PS, The wand is very small, and hard to click.
No other bugs I found.