Make "Leech" a sloppy eater (tylertfb)

A cosmetic addition: strong hits with Leech occasionally turn monsters
into large blood explosions.

Note from Floodkiller: Modified commit to also apply to Bloodbane since
it exists in Gooncrawl.

crawl-ref/source/art-func.h

@@ -21,6 +21,7 @@
 #define ART_FUNC_H
 
 #include "beam.h"          // For Lajatang of Order's silver damage
+#include "bloodspatter.h"  // For Leech
 #include "cloud.h"         // For storm bow's and robe of clouds' rain
 #include "english.h"       // For apostrophise
 #include "exercise.h"      // For practise_evoking
@@ -30,6 +31,8 @@
 #include "god-conduct.h"    // did_god_conduct
 #include "god-passive.h"    // passive_t::want_curses
 #include "mgen-data.h"     // For Sceptre of Asmodeus evoke
+#include "message.h"
+#include "monster.h"
 #include "mon-death.h"     // For demon axe's SAME_ATTITUDE
 #include "mon-place.h"     // For Sceptre of Asmodeus evoke
 #include "nearby-danger.h" // For Zhor
@@ -1361,6 +1364,30 @@ static void _LEECH_equip(item_def *item, bool *show_msgs, bool unmeld)
     // else let player-equip.cc handle message
 }
 
+// Big killing blows give a bloodsplosion effect sometimes
+static void _LEECH_melee_effects(item_def* /*item*/, actor* attacker,
+                                 actor* defender, bool mondied, int dam)
+{
+    if (attacker->is_player() && defender->can_bleed()
+        && mondied && x_chance_in_y(dam, 729))
+    {
+        simple_monster_message(*(defender->as_monster()),
+                               " liquefies into a cloud of blood!");
+        blood_spray(defender->pos(), defender->type, 50);
+    }
+}
+
+static void _BLOODBANE_melee_effects(item_def* /*item*/, actor* attacker,
+                                 actor* defender, bool mondied, int dam)
+{
+    if (attacker->is_player() && defender->can_bleed()
+        && mondied && x_chance_in_y(dam, 729))
+    {
+        simple_monster_message(*(defender->as_monster()),
+                               " liquefies into a cloud of blood!");
+        blood_spray(defender->pos(), defender->type, 50);
+    }
+}
 
 ///////////////////////////////////////////////////
 

crawl-ref/source/dat/descript/unrand.txt

@@ -100,7 +100,8 @@ the vividly coloured faerie dragons ever existed.
 demon blade "Bloodbane"
 
 A blade forged in Hell by the sacrifice of countless tortured souls. It
-inflicts the rage and suffering of those souls upon its wielder.
+inflicts the rage and suffering of those souls upon its wielder, leaving
+behind a mess of blood and gore.
 %%%%
 scimitar of Flaming Death
 
@@ -768,8 +769,9 @@ reveals the machinations of those who would prefer to stay invisible.
 %%%%
 demon blade "Leech"
 
-An unerringly vampiric blade which gorges itself on drained life force every
-time it strikes.
+An unerringly vampiric blade, forged in Hell by the sacrifice of countless
+tortured souls. It gorges itself further on drained life force every time
+it strikes, leaving behind a mess of blood and gore.
 %%%%
 dagger of Chilly Death