Dummy

Dummy is a kind of an artificial tee-helper. It's controlled by one player and serves more as a support for ourselves. Playing with dummy often allows player to finish a map alone, without participation of second person. Some clients provide special features in order to command and control our dummy (e.g. toggling between dummy and main character, copying moves, auto-hammering). Player is also usually able to change dummy's name and set up colours of its body. There are some maps designed especially for playing with dummy. Unfortunately, playing only with dummy on many race maps (especially brutals) may be very troublesome or even impossible.

Advantages

 * It may replace participation of second person
 * Allows to finish many maps alone (for instance: all novices)
 * "Second chance" when you fail with your main tee
 * Simple control - special features/commands/binds
 * Maps designed especially for playing with dummy

Disadvantages

 * It's brainless (itself)
 * Impossibility of doing different things using both tees at once
 * Difficulty or impossibility of playing at most of maps
 * Dummy-change time (average 0.2 - 0.8 sec, depends on ping)
 * It won't replace relations with real players :-)