As Silvi scored the blob, she might have noticed something a bit off about it, but then again it was a blob of fossilized grimm, it was always going to be "off". 
"You see miss Silvi that is where you are wrong, these ancient blob forms are interesting to look at and unseen before or outside this area. Now, may i ask the class what is the significance of this?" He asked the group in general. 

Now is when Mika piped up. "It is important because you can run into unique variants or unseen grimm and need to be able to identify weakpoints at a glance..." she said, happy to be in the hot cauldron. 

The doctor walked over to the blobbed ones. "Exactly my point. now who can identify possible weakpoints to attack on these?" he asked and gestured to them. The blobs had a porcelain-like mask and was otherwise featureless.