Millipede

The gameplay of Millipede is similar to Centipede but differs mostly in enemies:

Earwig: same as the scorpion in Centipede, making mushrooms poisonous so that the millipede will charge straight to the bottom of the screen after touching them.
Bee: same as the flea in Centipede, dropping mushrooms in a vertical line and requiring two shots to kill.
Spider: same behavior as in Centipede, bouncing irregularly across the lower portion of the screen. Multiple spiders can appear at the same time on higher levels.
Inchworm: when hit, slows all enemies for a short period of time.
Beetle: crawls around the player area for a while, then climbs up and leaves the screen, turning any mushrooms it touches into indestructible flowers. When hit, everything on the screen scrolls down one row.
Dragonfly: drops mushrooms while zigzagging down, and can be destroyed with a single shot.
Mosquito: bounces off the sides of the screen as it descends. When hit, everything on the screen scrolls up one row.
DDT bomb (stationary): can be blown up with one shot, destroying all enemies and mushrooms within the blast radius. Whenever the mushrooms scroll down, a new bomb is added at the top of the screen. Up to four bombs can be in play at one time.
All flowers and poisoned/partially destroyed mushrooms revert to normal, whole mushrooms when the player loses a life.

Source: TheGamesDB