LEGO Batman

The Joker becomes available in Villain mode, Chapter 3, episode 1. Walk up someone and press B, can be your partner too.

this is probably best done in the hideout where you go into all the levels as there is an infinite supply of people to shock.

Right when you start 3-1 on the Villian side, start using it on Harley, if you have on extra hearts it takes 6 shocks before she dies, so just shock her until she dies 5 times and the achievement is yours.

This achievement is only pops up when you kill 30 "anything" but be sure you are not in co-op. It only works when you are playing alone!

You'll need to complete at least one chapter in Story Mode before you play other characters besides the ones played in the Story Mode chapters in Free Play mode. In the Batcave, take the southwest elevator up and go to the giant computer. There, you would have an option to enter a code. Type in this code to unlock Joker (Tropical):

CCB199

Next, go to a chapter in free play mode and select Joker (Tropical). Progress throughout the chapter while killing enemies by pressing the to electrocute them with Joker's buzzer. This is also a good chance to unlock this achievement:



If you want to earn the "Start of something wonderful." achievement, switch the two characters into Joker if not already and electrocute one Joker with a different Joker by pressing the button.