A one-man group
Group projects can be heaven and hell. Heaven for the students who don’t want to contribute, and hell for the group members who have to carry said leeches. One time, a teacher asked the students to form groups of less than seven people. A particularly astute student realized what the teacher said and created a group of their own.

They weren’t breaking any rules. After all, a one-person group contains less than seven people, right? The teacher couldn’t come up with a response, and the student was free to do what they liked. In the end, the student got a grade they deserved (we hope it was an A).