I have been on a really productive streak lately in my 4e game as far as generating new material. Most of the time I spend doing DM prep work is in creating new individuals or species for the party to encounter and detailing environments and locations for those encounters to happen in.
Twists and turns in the game have led the party to leave the jungle that they have been adventuring in for a couple dozen sessions and explore an alien planet in another dimension. Different dimensions in my game have different rules for how energy and matter behave. This planet has a solid metallic core that slowly cooled, forming well separated bands of different metals at different depths. Some of these metals can take a gaseous form if subjected to an intense energy charge, and some take a crystalline form when the gaseous form is cooled. Some of the metals have natural connections through shadow to other dimensions, giving them wondrous properties such as 10 x elasticity or compounding energy storage.
During the planet's summer, when it is closest to the sun in its very elliptical orbit, the heavy gasses of the atmosphere stay a few thousand feet above the surface of the planet, but during the long winter the planet grows cold and the gasses blanket the surface. Most of the planet's biomass lives in the atmosphere; the bottom of the food chain are tiny chemosynthetic organisms with bouyant gas bladders which produce a strong bioluminescence as a by-product of digesting metallic gasses. The light visible on the planet's surface is entirely the result of these glowing zooclouds.
During the winter storms, cold winds send tons of atmospheric life smashing into the planet's surface. An entire ecosystem that mostly hibernates during the summer and comes to life in the winter specializes in cleaning up the detritus, eating the cleaner-uppers, eating the eaters, etc.
I have made up dozens of alien species, many blurring the line between plant, animal and insect. And luckily I can now post about them even before they are discovered by the party! Last session Tilia and a giant elder dragonfly creature shared a mind meld (Tilia has a nature spirit living inside of her which facilitates such things). The ancient creature imparted thousands of years of encounters with the planet's denizens to Tilia, nearly killing her in the process with an overload of energy to the brain. I gave Tilia a bonus to knowledge and nature checks conducted on this planet as a result, but I also thought it would be fun to post some creatures here so Mike (Tilia's player) can actually gain some real game knowledge that might be very useful... starting with the creatures that were swooping in to engage Tilia in combat when we paused at the end of last session!
Ice Fly (adult form) Initiative: +50 (superconductive nervous system) Stealth: +25 Perception: +25
HP: 30 Movement: 15 Flight Hover
AC: 40 Shift 5 Fly as a minor action
WILL: 30 (an incoming attack must hit the WILL defense twice to connect - superconductive nervous system)
Aura 1: Stinger Spine Aura: Any creature that starts its turn in, moves into, or has the aura move past it suffers the following attack: Im. Reaction, melee +30 vs. Reflex, 5 dmg, ongoing 5 (stackable) save ends. All damage done by the stinger spines also deals stackable ongoing damage because shadow connections are made that enable the ice fly to keep pumping a very effective cocktail of anticoagulents and uppers into the victim until a successful save is made. Any creature taking 20+ points of ongoing damage from this gains an extra minor action, taking 30+ gains an extra move action, taking 40+ gains an extra standard action due to the stimulant effect.
Basic Attacks: Stinger Spines (melee +35 vs REF, 3d6+5, ongoing 5 [stackable] save ends);
or Pincer Mouth (melee +35 vs REF, 2d12+8 and slowed save ends. The target is also marked.)
Standard Attacks: 2 x Tail Stinger Spines OR Tail Stinger Spine/Pincer Mouth combo
Recharge 4,5,6: Blinding Dance: Close Burst 10, +25 vs Will against all enemies in burst, Dazed and Blinded, save ends at -2, and the ice fly can teleport to any point within the burst.
Recharge 6: Swarming Flies: Remove ice fly from play. Place 4 ice fly tokens at the corners of a 5 x 5 close burst 2. Each token has Aura 1 Tail Spine Aura and cannot be targeted by melee attacks. Each token shifts 10 squares. Remove ice fly tokens from map and place ice fly at any point in the original burst. The ice fly gains 40 temporary HP.
Encounter: Ice Fly Arrow: move 30 fly (must move at least 10) and make the following attack at any point during the move: +40 vs. REF, 5d12 dmg +Blinded +Slowed, save ends at -2, and the target is marked.
Mark: If marked enemy takes a move action, the ice fly shifts 10
The ice fly is a feared predator of the boundary between the red layer and the uppermost blue layer of the atmosphere. Its exoskeleton is metallic crystal, and its nervous system is entirely made up of a superconductive metal that actually transmits signals many times faster than the speed of light.
Nymph Form: Ice Fly Nymphs live in liquid gas lakes that pool on the upper surface of the floating living islands in the red layer of the atmosphere. They are also feared predators.