I made a couple of these for a Yuri's Night (http://www.yurisnight.net/) party. The alien sits in a glowing liquid and the effect looks pretty cool in a dark room.
The materials required are
1) A jar with a lid that is thick enough to conceal a battery pack and some LEDs
2) Glow water made from florescent dye extracted from a highlighter pen (http://www.youtube.com/watch?v=eTsgPLmli8E)
3) Alien Embryo Growing Pet (http://www.thespacestore.com/alemgrpet.html)
4) 4.5V Battery pack (https://www.instructables.com/id/Making-a-45-volt-battery-pack-from-a-9V-battery/)
5) Protostack half size prototyping board (http://www.protostack.com/index.php?main_page=product_info&cPath=1_2&products_id=3)
6) 2.7 ohm resistor (1W)
7) 6 x High Power Ultra Violet LEDs (http://www.protostack.com/index.php?main_page=product_info&cPath=24_30&products_id=36)
Step 1: Grow the Alien Embryo and Immerse It in Glow Water
Put the alien egg in water for about 3 days. During this time it will break out of its egg to about 3 times its original size.
Fill the jar with the glow water and place the alien embryo inside.
Step 2: Cut the Prototyping Board to Size
The prototyping board was slightly too big for the jar I selected, so I cut off about 1 cm from each end. This was a simple case of scoring and snapping the board.
Step 3: Add the Resistors and LEDs
Add the LEDs and resistors. You will note 2 pen marks on the board. This is where the 4.5 battery pack will be connected to.
Each LED has 2 leads, with one lead shorter than the other. The LEDs are connected directly to the positive and ground power rails with the short lead going into the ground rail.
On this particular board the positive rail has a solid white shading, whilst the ground rail has just the outline.
Step 4: Spray the Board With a PCB Varnish
We want some degree of water resistance as the glow water may splash onto the board. A PCB varnish will help here.
Step 5: Add the Battery Pack
Solder the 4.5V battery pack onto the board
Step 6: Tape Up the Board and Add Double Sided Tape
Tape up the board with electrical tape to give it another level of water resistance then add double sided tape to the bottom.
Step 7: Stick the Board to the Inside of the Lid
Step 8: Sit Back and Admire Your Handywork
Pop the lid onto the jar, turn the light off and enjoy.