This is what it says on the tin. It is a timer that spawns a mob that is burning.

1. Place down a command block.
2. Paste this command:
1.8 and lower:/summon Villager ~ ~1 ~ {CustomName:TIMER,CustomNameVisible:1,NoAI:1b,PersistenceRequired:1b,CanPickUpLoot:0b,HealF:60,Attributes:[{Name:"generic.maxHealth",Base:60}],Fire:1277951,Silent:1,Age:0}
1.9:/summon Villager ~ ~1 ~ {CustomName:TIMER,CustomNameVisible:1,NoAI:1b,PersistenceRequired:1b,CanPickUpLoot:0b,Health:60,Attributes:[{Name:"generic.maxHealth",Base:60}],Fire:1277951,Silent:1,Age:0}
1.10:/summon Villager ~ ~1 ~ {CustomName:TIMER,CustomNameVisible:1,NoAI:1b,PersistenceRequired:1b,CanPickUpLoot:0b,Health:60,Attributes:[{Name:"generic.maxHealth",Base:60}],Fire:1277951,Silent:1,Age:0}
1.11:/summon minecraft:villager ~ ~1 ~ {CustomName:TIMER,CustomNameVisible:1,NoAI:1b,PersistenceRequired:1b,CanPickUpLoot:0b,Health:60,Attributes:[{Name:"generic.maxHealth",Base:60}],Fire:1277951,Silent:1,Age:0}
1.12:/summon minecraft:villager ~ ~1 ~ {CustomName:TIMER,CustomNameVisible:1,NoAI:1b,PersistenceRequired:1b,CanPickUpLoot:0b,Health:60,Attributes:[{Name:"generic.maxHealth",Base:60}],Fire:1277951,Silent:1,Age:0}
1.13:/summon minecraft:villager ~ ~1 ~ {CustomName:"\"TIMER\"",CustomNameVisible:1,NoAI:1b,PersistenceRequired:1b,CanPickUpLoot:0b,Health:60,Attributes:[{Name:"generic.maxHealth",Base:60}],Fire:1277951,Silent:1,Age:0}
1.14+:/summon minecraft:villager ~ ~1 ~ {CustomName:"\"TIMER\"",CustomNameVisible:1,NoAI:1b,PersistenceRequired:1b,CanPickUpLoot:0b,Health:60,Attributes:[{Name:"generic.maxHealth",Base:60}],Fire:1277951,Silent:1,Age:0}
All of these are set to one minute.
NOTE: I measured this: Setting it’s health will extend [​or shorten] the timer to that many seconds.

[​60HP] 1 Minute
[​120HP] 2 minutes
[​757555577929859202848498483929378] One eternity and 61 Seconds
Use this in Redstone/Command block contraptions as well, a timer!