The Heatscar Spider is the Nether variant of the Overworld Spider. It is larger and has 50 HP (25 hearts), more than three times that of a normal spider, which has 16 HP (8 hearts).
It attacks much like the Vanilla Spider: jumping on player while attacking. It will light the player on fire upon attacking. It is recommended not to fight with a melee weapon unless wearing armor; instead you should use a bow from a distance. When you kill the Heatscar Spider, Baby Heatscar Spiders spawn where it died. The Baby Heatscar Spiders will also attack you.