Snubstitute

To snubstitute is to non-consensually replace something that belongs to another person with something of lesser value.

Likewise, a snubstitute teacher is a substitute teacher that is actually more annoying than your regular teacher.

1) "Jimmy snubstituted my Coke for Diet Coke again, what the hell?"

2) "Mrs. K is horrible I hate her. She's more like a snubstitute teacher."