Can you use eldritch blast and grasp of the deep (the lurker in the deep patron) at the same turn?

In the Aberrant Lurk Unearthed Arcana rules is stated as:

At 1st level, you gain the ability to magically summon a spectral tentacle that strikes at your foes. As a bonus action, you create a 10-foot-long tentacle at a point you can see within 60 feet of you. The tentacle lasts for 1 minute or until you use this feature to create another tentacle.

When you create the tentacle, you can make a melee spell attack against a creature within 10 feet of it. On a hit, the target takes 1d8 cold or lightning damage (your choice when it takes the damage) and its speed is reduced by 10 feet until the start of your next turn. When you reach 10th level in this class, the damage dealt by the tentacle increases to 2d8.

As a bonus action on your turn, you can move the tentacle up to 30 feet and repeat the attack.

You can summon the tentacle a number of times equal to your Charisma modifier (minimum of once), and you regain all expended uses when you finish a long rest.

So you use a bonus action to conjure it, then you can do a melee spell attack, but this melee spell attack count as an action? If not, you can eldritch blast and hit with the tentacles, right? And if it does, can you just eldritch blast and then use the second hit as a bonus action? I know that Tasha’s already released an official version, but I liked this one way better.