I will be blunt here. These two should NOT deal damage to you at the end of the round, especially the spiderlings. They scale off Elise's level so if you got screwed over by RNG or your team is idiotic enough not to focus on the main threat (Hate you Kha'zix), and she transforms just before the end, RIP to your health bar.
Last game I had was with me having around 35 HP... lost all of that because the enemy had 3 3 stars, one being Elise and once Elise changed into her spider form, suddenly there are 7 3 star champions... I took over 40 damage that round and lost instantly... Seriously, why is she being buffed again Riot?
If the Spiderlings didn't give damage to you then it wouldn't be so bad but as it stands? It is so unbalanced and unfair like the majority of this mode.