NonsequitaurCreature 3
Perception +9
Languages Common, Elven, Fey
Skills Athletics +11, Diplomacy +6, Intimidation +6, Nature +7, Survival +7
Str +4, Dex +2, Con +1, Int +0, Wis +2, Cha +1
AC 20; Fort +8; Reflex +9; Will +9;
HP 40
Speed 40 feet
Hoof
+9 (+5, +1) to hit (agile) 1d10+4 BludgeoningSpear
+11 (+6, +1) to hit 1d4+6 PiercingSpear
+9 (+4, -1) to hit (thrown 20) 1d6+4 PiercingCentaur out of Nowhere

Trigger The PCs round a corner, open a chest or door, unmask a villain, or draw back a particularly plush curtain
Requirements The PCs are not thinking about centaurs
Effect A nonsequitaur appears whenever it is least expected. A nonsequitaur comes into being and everyone rolls initiative.
At Least That's Over
Trigger The nonsequitaur is reduced to 0 Hit Points
Effect It isn't, not yet. The nonsequitaur uses MORE! CENTAURS! as a reaction, then dies.
Forget about Me?
Trigger The nonsequitaur leaves the field of view of all of the PCs
Effect The nonsequitaur feels ignored. It uses MORE! CENTAURS! as a reaction.
You Should Have Paid Attention to the Centaur
Trigger A creature ends its turn without attacking, casting spells at, using skills on, or otherwise acknowledging the nonsequitaur
Effect The nonsequitaur dominates all forms of interaction. It uses MORE! CENTAURS! as a reaction.
MORE! CENTAURS!
The nonsequitaur decides that this could be improved by more centaurs. It causes another nonsequitaur to spontaneously come into being in an unoccupied space within 60 feet.
Before you ask, YES this summoned nonsequitaur can use MORE! CENTAURS! as well, NO this is not a design oversight. I write the blog, them's the breaks.
Trample
Medium or smaller, Hoof, DC 18 reflex
The monster Strides up to double its Speed and can move through the spaces of creatures of the listed size, Trampling each creature whose space it enters. The monster can attempt to Trample the same creature only once in a single use of Trample. The monster deals the damage of the listed Strike, but trampled creatures can attempt a basic Reflex save at the listed DC (no damage on a critical success, half damage on a success, double damage on a critical failure).
Traits
Anything that doesn't list another rarity trait (uncommon, rare, or unique) automatically has the common trait. This rarity indicates that an ability, item, or spell is available to all players who meet the prerequisites for it. A creature of this rarity is generally known and can be summoned with the appropriate summon spell.
BeastA creature similar to an animal but with an Intelligence modifier of –3 or higher is usually a beast. Unlike an animal, a beast might be able to speak and reason.