The "with" keyword in Delphi.

It allows evil code like this:

SomeObject.SomeProperty := 'Value1';
SomeOtherObject.SomeProperty := 'Value2';
with SomeObject, SomeOtherObject do 
begin
    SomeProperty := 'Who Knows which one is being set!';
    // 50+ lines of code using the Objects without needing the actual object.
end