1. Floating fish tank- a ball of water floats around the room, with fish or other exotic sea creatures in them. Great for studies or other brooding spots. Not so great for parties (lots of dead fish).
There are a bunch floating around the room, wide circular arcs:
- Standard exotic fish, not harmful, but getting smashed into one hurts like hell (1d4 damage) and you have to live with the death of a fish on your hands. Unless otherwise noted, all glass bowls do this damage when either knocked into or used as a throwing weapon.
- A razor fish in just a floating sphere of water, no glass. Inside is a small island with a toy castle and some (real) gold pieces. Smashing the ball around won't pop it, the enchantment that holds the water is inside the castle, and must be dispelled. It would be difficult to hit the piranha inside, as the dispersion of the water flows around strikes in unpredictable ways. No glass means being hit by it doesn't hurt, but sharing a square with it means taking 2d6 plus a chance to bleed, cutting yourself on the razor fish.
- A bowl with a very poisonous jellyfish (fort save or slowly paralyze 'till suffocation), nearly invisible to the normal spectrum of light, making the bowl seem empty. There's a shiny diamond hidden in the sentiment of the bowl.
- Waterless tank full of colorful hermit crabs. Each actually is a vessel for a potion, eating a crab will count as "drinking" the potion. Red is for Healing, Blue for Resistance to Cold, Green for Cure Disease, and purple for Hermit Crab Empathy (a turn for each crab eaten, doing nothing but sobbing loudly for your crimes)
- A wishing fish. The wizard caught the wishing fish and let it go, and then wished for it to stay in this bowl forever. This makes the bowl indestructible and immovable in its wide arc moving through the room. It stares at you knowingly, and pityingly.
- Space Lobster. Its tank is a perfect square, and is full of acids essential to the creature's survival. (3d6 damage instead of normal on a contact smash). The lobster dissolves out of this dimension when the glass is broken.
- Sentient Coral, there are a few of these things floating around, and if all removed and combined in a larger container, it becomes a powerful psychic being. Very polite but very evil.
- Scroll Fish: Spell scrolls or a copy of the wizard's spellbook, written on thin white fish with long bodies. Impossible to read unless given a specific type of fish food, then form into the right order. The fish food is hidden somewhere else in the tower.
- Angry water elemental - if glass is broken it will be freed. 50% of ally or enemy.
- Mantis Shrimp - Glass is as tough as Adamantine. If broken or somehow opened, the Shrimp becomes giant. God help you.
Put these in a room with a random encounter and hilarity should ensue.
2. Chess Robots- Two large sophisticated robots (or golems if you wanna go that way) sit blocking the entire room with their large computational bodies and a small board game between them. They are equally brilliant and cannot beat each other.
A turn may take decades of computing and the robots will NOT tolerate any risk of the board pieces being jostled. This is reinforced with save-or-die death rays, which will be calmly explained to newcomers. They are happy to provide passage across the room for knowledge of other games.
Additionally, they have not learned the concept of cheating, which they will be very thankful for, and use to break a dead-even, decade long tie. Return visits after teaching the bots cheating will result in the bots continuing on as normal, but with their death rays trained on each other as a deterrent.
3. Forgotten Experiment - Gnashing teeth on twitching hooves, its braying and pleading for death. It probably cannot die. It would happy to help you kill the wizard, but it breathes noxious gasses and words come out in a broken version of the spell tounges - making its speech always unrecognizable.
4. Vacuum Room - completely devoid of atmosphere, probably being used to assist with temperature control in some experiment somewhere in the tower. Or, as always, perhaps just for the hell of it. The doors are unlocked but sealed tight, with a sign that says "Warning Do Not Open" in a magical, understandable-by-all rune. Opening leads to a explosive decompression. Strength to grab on to something or get smashed for like, 5d6 damage or something. Put breakable shit in here if you want to be more mean.
5. The Thing in The Box - It is large and made of metal. There is something inside. It cannot speak, but it does tap from the inside of the box. Somewhere there is a book which can translate the morse code. It can answer questions and the first few will be very reliable and useful. The next few will be useful, believable lies. The ones after that will be lies spun so well that when they go horribly wrong, it won't seem The Thing's fault. It's a slippery slope after that. You'll probably wind up becoming a wizard.
6. Dusty Workout Room - Abandoned and pathetic sets of weights litter the room. An animate training dummy weeps, for it has not known any living contact in a century. Fairly powerful magical melee weapons just lie around. If the wizard finds out you were in here, they will hunt you down out of shame.