diff --git a/src/map/skill.cpp b/src/map/skill.cpp
index a796625ffe..1a579d3c5f 100755
--- a/src/map/skill.cpp
+++ b/src/map/skill.cpp
@@ -16035,6 +16035,8 @@ int skill_unit_onplace_timer(struct skill_unit *unit, struct block_list *bl, t_t
 		case UNT_SOLIDTRAP:
 		case UNT_SWIFTTRAP:
 		case UNT_FLAMETRAP:
+		case UNT_GROUND_GRAVITATION:
+		case UNT_JACK_FROST_NOVA:
 			skill_attack(skill_get_type(sg->skill_id),ss,&unit->bl,bl,sg->skill_id,sg->skill_lv,tick,0);
 			break;