Custom TNT

/execute @e[type=cow,name=lava] ~ ~ ~ /setblock ~ ~ ~ tnt
/execute @e[type=cow,name=lava] ~ ~ ~ /summon armor_stand ~ ~ ~ {CustomName:"lavatnt",Small:1,Invisible:1}
/execute @e[type=armor_stand,name=lavatnt] ~ ~ ~ /entitydata @e[type=tnt,r=1] {CustomName:"Lava"}
/scoreboard players add @e[type=tnt,name=Lava] timer 1
/execute @e[score_timer_min=1,score_timer=80] ~ ~ ~ /particle lava ~ ~ ~ 0.5 0.5 0.5 0.1 10
/execute @e[score_timer_min=79,score_timer=79] ~ ~ ~ /setblock ~ ~7 ~ sponge
/tp @e[type=cow,name=lava] ~ ~-999 ~
/execute @e[score_timer_min=80] ~ ~ ~ /kill @e[type=armor_stand,name=lavatnt]

Format One Command :

INIT:/scoreboard objectives add timer dummy

/execute @e[type=cow,name=lava] ~ ~ ~ /setblock ~ ~ ~ tnt
/execute @e[type=cow,name=lava] ~ ~ ~ /summon armor_stand ~ ~ ~ {CustomName:"lavatnt",Small:1,Invisible:1}
/execute @e[type=armor_stand,name=lavatnt] ~ ~ ~ /entitydata @e[type=tnt,r=1] {CustomName:"Lava"}
/scoreboard players add @e[type=tnt,name=Lava] timer 1
/execute @e[score_timer_min=1,score_timer=80] ~ ~ ~ /particle lava ~ ~ ~ 0.5 0.5 0.5 0.1 10
/execute @e[score_timer_min=79,score_timer=79] ~ ~ ~ /setblock ~ ~7 ~ sponge
/tp @e[type=cow,name=lava] ~ ~-999 ~
/execute @e[score_timer_min=80] ~ ~ ~ /kill @e[type=armor_stand,name=lavatnt]