For moulds, use old plastic lids, for example from a crème fraîche tub or melt glue stick container. Just keep in mind that you will be cutting up the lid later.
Place the plastic lid with the inside facing up on a covered surface. Place plastic spiders, dried mealworms, or something else icky inside the lid. Remember to place the objects belly up. Spiders should have their legs up in the air.
Carefully follow the instructions on the package and blend about half the quantity of resin required to fill the lid. Pour the blended resin into the lid, so that your insect is in the wet mixture. After a few hours, air bubbles may appear on the surface of the resin. Simply pop the bubbles with a needle before the resin sets completely. Then let the resin set completely, even if the creepy-crawly isn’t fully covered.
Blend the remaining quantity of resin required to fill the lid up to the edge. Pour the resin into the lid and allow it to set for another day.
Cut off the plastic lid once the coaster has set completely.
Make a craft with hideous spiders, worms, and other creepy-crawlies that invade your home for Halloween! Then you can serve your guests a ghastly witch’s brew on glass coasters featuring cast creepy-crawlies. Items cast in resin tend to float up towards the surface, so it is best to cast the coasters in two stages to keep the surface smooth.
Note: Resin is a complex material, so take care to read all the pack instructions before starting and wear protective gloves.