It appears to be a mossy tree stump walking around on its roots, with three branches lashing around.
CR 3; XP 800
N Small Plant
Init +1; Senses low-light vision; Perception +5
AC 15, touch 12, flat-footed 14 (+1 Dex, +3 natural, +1 size)
hp 30 (4d8+12)
Fort +7, Ref +2, Will +2
DR 5/slashing; Immune plant traits
Speed 20 ft.
Melee 3 slams +6 (1d4+2)
Str 14, Dex 12, Con 16, Int 1, Wis 13, Cha 7
Base Atk +3; CMB +4; CMD 15 (27 vs. trip)
Feats Blind-Fight, Combat Reflexes
Skills Perception +5, Stealth +9 (+19 in forests and glades), Survival +2; Racial Modifiers +10 Stealth in forests and glades
Organization single, pair, or a school (3–10)
Stumplings are small plant creatures that mimic the appearance of a tree stump. They have animal-like intelligence and are not aggressive unless threatened or directed by a greater force, such as a angered druid or malevolent fey. Some stumplings can show a greater degree of curiosity, and keep following travelers and rummage through camp sites, as they show no fear of humans.
Despite their non-threatening nature a large group of stumplings was responsible for an outburst of war between two kingdoms—the creatures settled in peace a hilly region between the countries, and were mistaken to be results of lumbering operation violating the established border treaty. When the hostilities broke, a few acres of tree stumps got up and walked away bothered by the noise but it took whole day for the belligerents to realize what just happened.
Stumplings are sometimes herded by timber braves, kept as pets and companions.