The same as object, except it shoots thorns. Leaves corpse the same as cactus without thorns (unwalkable by default - place them carefully). Of course it doesn't move.
Code:
<?xml version="1.0" encoding="UTF-8"?>
<monster name="Cactus" nameDescription="a cactus" race="undead" experience="150" speed="0" manacost="0">
<health now="200" max="200"/>
<look typeex="2728" corpse="2736"/>
<targetchange interval="1000" chance="8"/>
<strategy attack="100" defense="0"/>
<flags>
<flag summonable="0"/>
<flag attackable="1"/>
<flag hostile="1"/>
<flag illusionable="0"/>
<flag convinceable="0"/>
<flag pushable="0"/>
<flag canpushitems="0"/>
<flag canpushcreatures="0"/>
<flag targetdistance="1"/>
<flag staticattack="100"/>
<flag runonhealth="0"/>
</flags>
<attacks>
<attack name="physical" interval="1500" chance="80" range="6" min="-30" max="-60">
<attribute key="shootEffect" value="eartharrow"/>
</attack>
</attacks>
<defenses armor="15" defense="15">
<defense name="healing" interval="1000" chance="20" min="10" max="20">
<attribute key="areaEffect" value="greenshimmer"/>
</defense>
</defenses>
<elements>
<element physicalPercent="10"/>
<element deathPercent="-20"/>
<element holyPercent="40"/>
<element earthPercent="80"/>
<element energyPercent="-10"/>
<element icePercent="-10"/>
<element firePercent="30"/>
</elements>
<immunities>
<immunity paralyze="1"/>
<immunity invisible="0"/>
</immunities>
</monster>