First it is staying out late, then it is not calling home, then wild parties, and before you know it your life will be completely out of control; someday you will be glad that you had a lockdown. Which informal fallacy is committed in the above argument?

The argument warns that one small step will slide unstoppably into total loss of control.

Staying out late leads to not calling home, then to wild parties, then to ruin.

Each link is assumed to trigger the next without any justification.

A minor first action is portrayed as inevitably ending in disaster.

Chaining ungrounded consequences toward an extreme outcome is the slippery slope fallacy.