Looks to me like they're just squares w/physics spawned from the enemy upon contact.
Try:
On hurtbox collision w/ Enemy |
Repeat 100 times | Enemy Spawn BLOOD_SQUARE Image Point (1)
On BLOOD_SQUARE spawned | Apply Impulse [random(1,2)] Angle ([andom(235,305)] Image Point (0)
On BLOOD_SQUARE collision w/ ground | Set BLOOD_SQUARE physics to disabled